What about HWQS WPMs? They help by having 6 outputs in a 4 gang opening, and they have a nice blank cover. Of course, if there are a lot of interfaces required this goes out the window.

The electrician saying 10-15k to relocate switch legs is basically him telling you he doesn't want to do it. This is obviously the correct way to handle the situation. Even with all the wiring coming up through the floor, low junction boxes could be installed, with 1 gang mud rings for receptacles with new conduit heading up to the roof. From there it's a piece of cake.

Modifying a device in anyway will negate the UL approval, and I don't understand why you would want to put yourself in that situation.