With the red pendants and modern hardware, it looks like your style 'wants' mosaics. I think a mosaic would look great! I think you can do something bold on the b/s -- everything else is neutral, except for the pendants. I don't think it would look too masculine. Maybe use a more muted colour for the b/s to 'feminize' it a bit if you are concerned about it. On the other hand: I love the subways posted by kitchenaddict. However, I think the red pendants would look out-of-place with the subways. I don't know...what do you think? It just seems like mosaics would be a more natural fit in this kitchen.

That's an awesome idea. Lots of color, texture, robust surface for grime, etc. I'd glue 'em down using a siliconized latex adhesive caulk. (Siliconized latex caulk has more adhesion than plain latex caulk, but is much more removable later than pure silicon caulk. An example is a product called White Lightning 3006) Run a generous bead on the inside half inch edge and a zig zag down the middle then press firmly against the wall, checking that they don't shift. This will hold them fine but is also removable later with care. Just make sure the back sides are clean, for the adhesion.

Beth H, thank you again for your thoughtful suggestions! Unfortunately, as I am in Canada, I won't be able to buy from TileBar. But it is great just to see the possible choices. I totally understand how my inspiration photo and my actual kitchen are totally different, it is just that I thought possible to borrow one isolated concept... Regarding the flat side of the island - yes, it does have a shaker style trim same as on cabinets, so it definitely looks more finished than on my mockup :) So, to sum things up, you advise against using slab backsplash on the window wall, no matter what style of tile backsplash we decide to go with, right?

I think doing a mix of different white tiles, or a mix of gloss and matte tiles might be easier to harmonize with the other two whites than having an expanse of a single white in the backsplash. These ideas are from Heath Ceramics. A mix of Heath's canvas white and vanilla bean. I don't know if I like this pattern for you, but I like the color mix. This is a dual-glazed tile; part of the tile is glossy and part is matte (I don't know if anyone but Heath does this, but you could mix gloss and matte tiles from someone else for a similar effect)