There are many times that we use wall cabinets as medicine/storage cabinets above vanities. If the matching medicine cabinet is no longer available, try buying the same width of wall cabinets that will match the vanity bases. Cut them down to about 4" deep unless you can order them reduced depth. The cabinets over the sinks can have mirrors inset into the door panels, and you can stil leave the others with standard doors. If it is a wall to wall application, the full run of 4"deep wall cabinets will give you the appearance you're looking for, without recessing them into the wall.

We were going to do that, but that turns out that it is cost prohibitive since we are trying to be very cost effective with this reno.