Can you reupholster the chairs you have now or make covers in grey for them?
If you don't have any chairs at all, my next suggestion is go to craig's list and see what you can find.
Best of Luck.

What about the Emeco Navy chair, in Flint?

The Emeco chairs are lovely, but hellaciously expensive and hard to sit on for long periods.

I think the CB2 Pony Tweed chair would add a nice, slightly softer element to all that chrome and glass. It comes in a nice charcoal, and is very comfortable. We have them for our dining room.

The Alta Shale chair would coordinate with the Silverado (same chrome) and is supposedly also comfortable. Never tried that one though.

Try Craigslist before you go dropping $200/chair, though. You might be lucky!

Ikea has something that might work... it only have a bit of silver on the legs but it has a similar feel to the ones posted

http://www.ikea.com/ca/en/catalog/products/00201334/

I also have the CB2 Silverado round table. I bought it to go with vintage Brasilia chairs that I reupholsered in a gray and green abstract kind of floral. Anyways, you'd be surprised how well that warm brown wood goes with the glass and chrome of the Silverado. So, my idea for you is this John Vogel chair with a gray seat from West Elm: http://www.westelm.com/products/john-vogel-chair-g656/?pkey=cdining-chairs-seating.

I have Crate and Barrel's folio chairs in black, now for about 4 years, i adore them. they come in a variety of colors including "ash." it's very pretty and i was disappointed that it was released after i had already committed to the black ones. they are great chairs, comfortable and clean up nicely, even once in a while i rub them down with some leather care stuff, and by once in a while i mean twice in 4 years. they still look great.

http://www.crateandbarrel.com/search.aspx?query=folio

They have these new gray chairs at Crate and Barrel. I like the low profile and rounded back.

http://www.crateandbarrel.com/curran-side-chair/s490060

A little roundup of the industry.... I have worked for C&B, Z Gallerie and now Bo Concept. All have a similar chair - as does Room & Board, and several other retainers. Bo Concept has by far the best price - but the Crate and Barrel chair, as well as that in Room & Board's selection have by far the best quality.
When at C&B I sold more than $75 thousand worth of the Folio chair for restaurant and commercial use. There is some problem with extremely heavy use of the bonded leather peeling, but in home use this is not an issue. The Chinese top of the line furniture maker Maria Yee makes the chairs for C&B. They are twice as much, but twice as well made... and I say that selling a competitors product.

I have exactly what you need! I have these in creme and it's exactly what you're looking for: http://www.overstock.com/Home-Garden/Jazzy-Bonded-Leather-Grey-Side-Chair-Set-of-2/6585119/product.html They look to be out of stock currently but keep checking back/call the Overstock people.

I apologize for the late reply to these messages. Unfortunately, I had some issues logging into the site. All of these ideas are extremely helpful. I'm not sure which one I'll do just yet, but I have been looking into almost all of them.