I'm putting two sinks into a 56" vanity for my girls' bathroom (4 girls share it). I'm installing Kohler Caxton, but can't decide whether to install the small or medium size. I noticed in the Kitchen-Bath store that on the medium Caxton, the granite over-hang was more than I would have expected for an undermount sink, especially at the upper drain hole edge. In effect is to give you a little more counter space. Plus, you couldn't see where the sink met the granite. That "line" was covered by the overhang. The bath shop gave me a pair of templates for each sized sink, I will figure out which works best. We are replacing these really ugly, whipped avacado looking cultured marble shell shaped sinks, which each measure 19" across. The Caxtons measure about 16.5 and 15 inches from side to side. Any change is a good one and will result in more counter space regardless of which sink size I choose.

I think a bath bar positioned vertically between the two mirrors would look great. They probably wouldn't be as wide as wall sconces. Some of the are a small as 4 inches in width. Most bath bars can be mounted horizontal or vertical. The pictures below are from Tech Lightings web site. My daughter just put the first one horizontally in her bath and it looks great. My sister has the second ones placed vertically in her in her bathroom. The lights are pricey but very good quality. The have quite a few other styles. The lights generally come in a few different finishes and you can usually choose fluorescent or halogen and sometimes LED.

Here is your dilemma. if you take down those fixtures there will be two holes in the mirror, that being said, they will be up high and most likely off center. So, to get new lighting that is not stuck in the corners, and covers the holes behind it, might be next to impossible unless you run a thick bar that covers the space. But some times back in the day they only drug wire over and did not put in actual junction boxes, so the bringing it to code might be another issue. 1. take one of the lights down and see what is going on 2. probably have to replace the mirror and move the electrical location.

I have a sink and lowered vanity area in my master bath. I have a custom mirror treatment with wall to wall mirror and then decorative mirrors which demarcate the sink versus seated vanity area. The sink has two vintage sconces which are for styling and the seated vanity area has a lit "Hollywood style" lighting arrangement. I have a small master bath (urban high rise) and the mirrors certainly do increase the feel of space and light. Here's a picture when I was moving in