I went with a pretty simple setup -- 3000K white side-emitting LED tape, which I applied inside the cove area for a nice indirect light. I used a manual dimmer a lot like the one previously mentioned. I'm pretty pleased with the results.
I measured the power draw as 37 watts at full brightness, although I don't expect to have them turned up that high most of the time.
1990 E-250 Sportsmobile w/ penthouse top, converted when new by SMB Texas.