Our hood was built for us by a stainless steel fabricator. I'm quite sure they could easily surround your hood with stainless for very little money :) Just call a fabricator and ask for a home visit to see what they can do. You could also plaster that hood easily. Then add a simple tile trim to the edges, or a nice wood edge (ie a crown molding.) That's what I'm doing with my hood (my metal portion is an insert). I'm also adding granite tiles but as someone mentioned, the weight is an issue. I had to do a great deal of reinforcing to make mine strong enough to hold the stone and the insert. It's actually hung inside the box from heavy chains set into ceiling joists and then bolted into the wall joists as well on the backside. It's the kind of thing you do before you hang a hood, not as an after hung fix. I can plaster right over this box, so I'm sure you could do the same. Plaster isn't like paint...it sticks very easily. I'd probably do a coat of primer first, but then you could go for it! I think trying to pick a light color from your granite would be the way to go...I will be doing my wall color to try to minimalize the size of this monster: I'll have tile on that flat portion, then trim above and below that, and on top will be the venetian plaster. You could easily work with something similar...and even change the shape a bit if you wanted to by altering the wood frame and replacing with plywood. (We used marine grade ply to avoid warping and add stregnth). You have a stunning kitchen...why do you want an inconspicious fixture???? I personally would put some dough into that portion of your kitchen. It's the final thing missing from a great spot.

I just wanted to say that I love the 4" LED can light right over my sink. I have a 6" can about a foot away from that and it doesn't light up the sink when I'm doing dishes like the one just above it does. They're on two separate switches so I can have one or both on. I know you have two on each side, so maybe yours will be different. We did the 6" can lights in the rest of the kitchen and one 4" and I can't decide if I like the 4" among the other five 6" cans. Maybe yours won't be as noticeable since you're using 4" and 5". Let me know if you want to see pics of my lights as an example and Good Luck! Lighting design isn't easy :)

Actually the light I had posted is a new style of LED light - it does not require any large recessed lighting can so it is much easier to install - you just need room for the small junction box and to have the ability to snake lines through the ceiling. If you don't want to do that - the flush mounts everyone is posting for you are great!!! You could do one of those in the center and then add the recessed in the soffit above the sink....

There are a million directions you could go. Have you looked through pics on Houzz and saved any you like? Do you prefer chrome, brass, painted, floral, bright colors, black? Antique, mid-century, blown glass, modern, etc., etc., etc. You get the point. We need a better idea of your style!