Thank you so much for all your votes/comments about the shelf colour! We have decided to go with "White wash pickling stain". You can see the first coat going on below.
It's going to be hot, trust me (I have good colour imagination). And if we no likes, we can always paint the shelf white in a few years. Can't go back and choose stain once we've painted, so this seems safest.
Now, for help with the wall colour. I am thinking of "griege" - that's gray mixed with beige, yo! Is it gray? Is it beige? That's the colour I'm going for, with maybe the slightest suggestion of a purple-ish undertone.
So far my fav I've found is Loggia by Sherwin Williams. Do you have a favourite "griege"? Keep in mind the shelves may have the slightest green tinge, due to the poplar.