It's difficult to picture your set up based on your description. Do the ends of the vanity run into opposing walls? Would the medicine cabinets be on these walls facing each other? Will sconces be above the medicine cabinets?

Provide more details so you can get some suggestions.

The vanity is in a three walled alcove. If I get a surface mounted medicine cabinet it will be on the 60 inch wall. So for example a single Robern cabinet might be 15 inches which is too small but 3 of these combined might be the right size for this space. I really don't want to spend that much on a medicine cabinet so looking at others but wondering how big it needs to be so not to look undersized. The sconces would be on the same wall as the medicine cabinet - one on each side. Hopefully this explains it better.

I have a better picture now.

I agree a 15 inch wide cabinet be too small. If you got a wider cabinet 20-30 inches you could put the sconces on either side. I think this would look to scale.

If you are looking to save some money, how about a light fixture above the cabinet and using your old mirror by cutting it down into two pieces placed on each side of the cabinet? This would give you a the look of a full wall mirror.

Is it possible to put the cabinet on one of the side walls? If yes, then cut the mirror down to 30 inches wide and then install sconces on either side. I think this would look better if the cabinet could be installed flush to the wall.

Thanks! I actually have a small medicine cabinet on the side and don't want that arrangement in the remodeled bath. I'm pretty much planning to completely change what's there now.

I recently looked at the IKEA "Godmorgon" mirrored wall cabinets. They are actually very nice in person. If I'd been able to make the dimesions work I would have used them in a heartbeat. They are about 39" tall and come in a whole bunch of different sizes. I expect you could put 2 or 3 together to make a larger expanse of mirror, too. (That's what I wanted to do... but could not make the measurements fit ) They come in various widths with 2 doors or one door.. two separate links below:

http://www.ikea.com/us/en/catalog/products/60147645
http://www.ikea.com/us/en/catalog/products/20148996

staceyneil - thanks for the tip on Ikea. I went and checked those out today and they are nice - and economical. I've been sizing things up and I actually think 30" inches of medicine cabinet would be about enough if I have sconce lighting on each side rather than lighting above. Now I have to figure out how high to go - and how high it would be mounted - which will probably depend on the height of the tile wainscot.