It sounds like a very exciting project, much better than trying to retrofit for a glass display.
You're right about North America having outlets into which lamps are plugged being controlled by a wall switch. It should be a relatively easy thing to do, just have the outlet boxes in one room that will have lamps plugged into them on one circuit and controlled by a wall switch. In Canada, the outlets are have two plugins per wall receptacle. Standard procedure is for one to be on the lamp circuit and the other on a separate circuit. Reduces the chances of overloading the circuit, I presume.
The one problem with see through cabinets is that you don't see the in the display clearly, as you see through to the other room and what's in it. It also makes it a little more difficult to light the display as you have to go with either lighting from above or install track lighting. What appealed to me, and what's I'm planning to do, is to take out the wallboard behind a display and install slim fluorescent tubes behind sheets of opaque plastic. You could build custom shelving for the glass or use an existing display case. Modernist glass in NZ show something like this for a home display and it's very effective.
Good luck. Sounds like great fun.