Remodelfla used a great bs with her soapstone. It would be good to peek at hers to see how it came out (spoiler alert: gorgeous!).
If you went with soapstone as the bs, I think you'd have to commit to higher than the 5.5"because it might look odd to the sides of the window. It would end up like a broad dark stripe painted with a wide brush. It might be good as the bs for the stove though.... with tile the rest of the way. Of course, a full bs in ss would be gorgeous, but since you mentioned the counters were already a "splurge" that might cost too much.

The soapstone sounds very pretty, but what are you doing with the rest of the space? Are the walls staying white (with white cabinets and backsplash) or are you planning to paint them another color? Are there going to be window treatments?

Your choices sound more traditional, but the peak feels a little more contemporary. Are you thinking of classic choices, with a contemporary edge? Just trying to understand what you want the space to feel like, when thinking about backsplash choices :)

Looking great so far. Wonderful ceiling and windows. Can't wait to see it finished!

I'd use a tile backsplash. There are so many interesting choices and keeping the grout clean is no longer an issue. Someone who is more "expert" can tell you specifics about the grout, but if it's done right it is easy to keep clean.

I spent a while searching out remodelfla's backsplash, so I've linked it below (scroll down a bit to the pictures). It's beautiful.

Here is a link that might be useful: Remodelfla's backsplash

If the kitchen is going to read fairly contemporary as a finished project you could do something relatively simple like a the 5-1/2" soapstone backsplash the width of the window only, behind the sink, and something like a piece of Starphire glass (low iron, so very clear, no green cast) behind the range up to the hood. Usually in this application it is back-painted the same as the wall color.

I suggest this because 1) I see a few "where to end it" issues with regards to a full backsplash in this kitchen, and (2) I don't think every kitchen needs a backsplash except something behind the range and sink.

I don't mean to offend anybody who has done the 3, 4 or 5 1/2" low backsplash of countertop material, but I do feel like the reason you don't see it so much in magazines and around here is because it's not done much anymore, and in my eyes, anyway, looks dated. I put one in in our kitchen downstairs (in 2005) and regret it now. Unfortunately it's not something easily taken out because the granite company cut the countertop knowing they had a large margin for error because of the width of the granite backsplash which is a lot thicker than tile. So.... for those reasons I'd definitely vote that you go with tile. You could always choose your subway tile based on what would fit nicely under the window -- they come in a lot of different proportions now. One more thought -- someone on here recently had a kitchen reveal in which they'd actually used a beadboard TILE - it was lovely.

Speaking of lovely, your kitchen is completely beautiful. I love the window wall -- and the whole orientation of it around that feature. Just stunning -- can't wait to see it finished.

A backsplash that runs evenly from the bottom of the upper cabinets, to the side of the windows and around, would look very nice and still be affordable. I'd take the backsplash up to the bottom of the vent, behind the range. White subway tile would be a classic choice and would go with your more contemporary windows, high peak and stainless steel appliances.

The wood floors and soapstone are more 'traditional' choices IMHO, but the subway tile will be a nice bridge, between the two styles. It's more fun to mix up styles a bit and you've made some excellent choices. I look forward to seeing your progress :)

It's crying for something fun :) Please don't do the ubiquitous plain white subway tile. Pretty color glass tiles would be cool.

I am just starting to look at cabinets and you have the exact look that I want. What brand are they?

Thanks everyone!!

dianalo, thanks for the suggestion re:Remodela's backsplash (very nice!). Not sure I understand about going higher than 5.5" for a ss backsplash. If we went with a soapstone backsplash, we were thinking of 5.5" up to the window trim and then stepping it down to 4" for the rest of the perimeter.

lavendar lass, we're definitely going for a more traditional look, although the ceiling is a bit more contemporary more by default. We've even considered attaching some beams in the vaulted ceiling to give it more of traditional look. The ceiling will likley remain white but, we'll be painting the walls (either a green or light gray). We are looking to use some simple window treatments (shades?) . We also have a couple of pendants from Barnlightelectric for over the peninsula. Hope this helps give you a feel.

Thanks mpagmom. It's good to hear that all-tile backsplashes aren't a problem for cleaning. Is that true for behind the sink and range also?

Thanks palimpsest, we're definitely going for more traditional as mentioned above. If you only have the soapstone under the window and glass over the range, are there generally problems with with just drywall everywhere else? Someone mentioned that variations in the wall may leave some separations between the soapstone counter and the drywall. Is that a real concern?

One complication is that we really need to finalize the soapstone layout and let them know if we want any soapstone for the backsplash. It might be easier if we could decide after the rest of the kitchen was together.

Keep your thoughts and suggestions coming as we're still searching.

I did a kitchen for someone else with no backsplash at all (the window sill behind the sink sat right on the counter and was the same quartz), and just a piece of glass behind the cooktop. No backsplash anywhere else, and it hasn't seemed to present a problem.(and she isn't the neatest cook either) They made sure the countertop fit well to the wall, which I would want anyway, because large gaps would not be acceptable. (I sometimes think the backsplash gives the fabricator an excuse to Not fabricate the back edge as well as the could).

Soapstone is a very workable material and could be fitted to any imperfections in the flatness of the wall if necessary.

In my own kitchen I did a 1" backsplash in the soapstone in order to have a level ledge to set the sheet of glass on. This was necessary because the lip of the range was right at the back of the counter and this piece of soapstone was fitted perfectly around this lip. Its so small it doesn't read as a backsplash and it also solves the problem of the seam of different materials right at the back corner.

Since soapstone is so easily worked, I have seen it fitted around irregular stonework. Your fabricator should be able to scribe it right to the wall if necessary to allow you to make a decision after the fact regarding the backsplash if necessary.

Thanks for the suggestions everyone.

belugacoop, the cabinets are Kemper.

It sounds like some sort of tile going to the soapstone countertop is the best choice. I wasn't aware before the re-model that most have gone away from the low backsplash of countertop material. Wonder if that will be the case long-term?