Yes, I noted on several sites I researched that there was no 4-unit ones... mostly tens and sixes. Don't know what that's all about. That's why I thought you should just call or email pdxrv to see if they can help you understand its construction and information enough to make your own repair if possible. And just because they don't show it on their website doesn't mean they can't get a 4-key one or direct you to a source. The control modules seem easy enough to come by, but the switch components not so much.
I've never had one apart or I'd try to answer your question. Buying an entire new switch box appears pretty spendy, but obviously from looking at some websites, including Intellitec's, it is an assembly of several components, which one can buy separately. Some say Intellitec isn't great for customer service, but a call or email to them may provide assistance. You might just need the clear switch assembly sans circuit board, probably $20-$25 if pdxrv can get it.
I went out and looked at mine, and as I thought, the cover plate has no screws so must snap on. I didn't want to break mine trying to pry it off, so you either have to risk that or consult someone who knows how to get it off. The switch boxes themselves are behind cabinet partitions and walls, not readily accessed from behind. So my suggestion is to consult with Beaver Coach Sales or someone familiar with harmless plate removal so you can get at the one clear key cover that's likely broken. Then you can either attempt a plastic-glue or epoxy repair, or order a 4-place clear key cover so you don't have to anty up for an entire switch module.
If anyone else on the Forum has had occasion to disassemble one of these Intellitec Multiplex switch boxes, please chime in here with advice for Robert on popping off the switch plate. I'd be tempted to use a small plastic or wood spatula under a plate edge, with a cloth cushion under it to protect prying against the wood. But again, prying in the wrong spot could break a tab. It may require pressing in from under one or more edge lips to release tabs, using a spatula or screwdriver; hopefully someone else here knows. The main thing is to take steps to protect the woodwork around it.
I'd still call BCS or one of the other Bend sponsors of the BAC for advice; their electrical and cabinet people likely do this switch plate removal regularly.
-Joel
