buehl, I would love to do that. It would be really pretty and add a lot. But the soffits extend 8 inches. The soffit is not level along its length by almost 1/2" so I would expect it's off otherwise affecting door openings as he mentioned. Currently there's a good drop. Maybe this is splitting hairs. It comes to 16-3/4" instead of 17" like I was seeing in showrooms (one was actually less than 17" in a high-end showroom). As for tall small appliances, I don't even have an electric mixer! I will someday. That would have to be used on the opposite d/w counter with low 8" shelves above. Not roomy but maybe not so bad. I'd never be leaving something like that out anyway for my lifestyle. Some of those coffee makers would be a problem but I don't think anyone would want to store it on the main counter (I don't use one myself). Other than a mixer, what appliances might be used that are taller than 16" when in use (lids open etc)? My blender, cuisinart, ice shaver, ice cream maker, all are comfortably under 16 inches. The big box KDs really don't get into these things. It seems they're just setting up some cabinets to fill the space to sell any old kitchen without going over many options or details. They usually say things don't matter. 27 inches provides a 19-1/2" backsplash. This looses 3" off both the sink and main cabinet. Still the 27" uppers but keeping the 21" cabinet over the sink with the arch running about even with the others. 30 inches provides a 16-3/4" backsplash if I'm arriving at all this correctly. Hopefully it would not work out to less than this at install issues.

A 4"-6" back splash is a nice height range. You may want to consider the faucet or mirror height to help guide the decision.

I have a similar question five years later: Is the 4" matching back splash now out of style? And how long will it stay out of style? Doubt that it would be possible to get a full matching back splash 14 years after the home was built. I am considering removing the 4" back splash and going with a complementary tile or, perhaps, a colorful wallpaper. Thoughts as to how long the short back spash will stay out of style? (I'm old enough to remember bell bottoms - the first time they were in style.)

You definitely should put a full splash on the wall that’s next to the range, it’s necessary. I think it will look funny and uneven if it’s not on both walls, even though it is not needed. Question though - will you be painting the walls a lighter color? I think it would look better with a color that closely matches the backsplash. IMO