I prefer the 17" x 14" Caxton http://www.us.kohler.com/us/Caxton-17-x-14-under-mount-bathroom-sink-with-center-drain-and-clamp-assembly/productDetail/Under-mount-Sinks/421128.htm?skuId=384921&brandId=1011727&isSeachPage=true&pageName=globalSearch&hash=id%3Dfilters%26startIndex%3D40%26scrollTop%3D0

you still could - you would have 6 panels in all - three on your side and three on your husband's - assuming it's roughly the same distance on both sides. Figure out your lighting first, then the mirrors. Once you know where the lights will go, the mirrors will fall into place. You definitely want side lights in this space. Using only downlights would be really awkward in this layout. You will need a mirror and light by your vanity, but you'll also want a mirror and light by your sink. I would do 3 mirrors total. One over your vanity and one over the sink and one over your DH's sink. Then do 3 side lights on your side - two on the outside and one in-between the mirrors. Two side lights on DH's side - one on either side of his mirror. You might want to swap your vanity drawer with the drawer bank. It's hard to tell but I think the symmetry would be better.

Well, doesn't the tile size depend, too, on how big your bathroom is(?). I think my tiler told me once that to use large tiles-- they don't look right unless you can have at least 3 (or 4) complete tiles in a row, either direction. Otherwise, he thinks large tiles don't work well. We used 14" square porcelain tiles in one of our bathrooms, set on the diagonal, with very very narrow grout lines. I really like the look (though I've read here that tiles set on the diagonal are a thing of the past!). Anyway-- I love the tiles on the diagonal, and I think it also makes the room seem bigger. In our other bathroom, we put in penny rounds, which just look like a beautiful mosaic-- really love those-- and no shower (free-standing tub)-- so grout issues just aren't a problem-- stays clean-- we're always barefoot.

On the subject of two sinks, it also depends on where your plumbing is located and how much plumbing work you want to do to have two sinks. A large rectangle sink would look good and work well. Remember that 54-60" of vanity top space gets chewed up pretty quickly when you put in two sinks. I hear clients say all the time "I wish I had more counterspace on my vanity!" I rarely hear them express a burning desire for two sinks. You can get a vanity sink base up to 36" wide, so the 27" sink is a possibility and two faucets are a good alternative to two sinks. Another thing I hear is the wish for more drawer space. A bigger sink on the top narrows down the space for drawers on the sides. Using the 60" possible dimension, go with a 30" sink base and two 15" drawer stacks on both sides. That will give you ample room for an oversize sink as well as separate storage for both of you. Zone 4 Architects also makes a good point about the nose of the toilet making space on the left of the vanity less accessible.