Remove the middle sconce so you can use two mirrors. A whole wall mirror is umm... not the greatest look. There are some really nice floating adjustable mirrors that would suit that style.

rollinggirl if we take out the middle sconce, I still think 2 mirrors wider than 22" will look off since they won't be centered on the sink. Or do you think it won't be noticeable once the middle sconce is gone?

I would remove all sconces I would get the mirrors that would fit and get lights above them. The most imp is to have mirrors centered and on point with the sinks. If you have room for lighting above mirror fantastic. However I disagree with the he thought that a full mirror is wrong. I think the best look and lighting I'll be achieved by mirroring the complete space and placing the existing sconces where they are.

I think once everything else is in you won't notice the missing sconce. You'll appreciate the mirror space more than the extra light bulb.

Since there is the bridge at the top, the full mirror idea could be the best look I agree. One other thought I had that I forgot to share, keep lights the way they are, center skinny mirrors over sinks, and add a 20" wide glass shelf under the center sconce, to make the middle space not look empty.