"interesting systems that guys have installed in the high end custom homes?"
This conversation can go two ways. PITA or whoa hip... Some are a mixture of each.
Japanese shoji screen room all wood joinery done by hand with no fasteners, except for those used in the hydraulic system used to raise desks and tables out of the floor.... Various controls for it were Crestron and Homeworks, hard part was developing an interface for it. And convincing everyone that 12000#'s of hydraulic double acting cylinder should include at least some safety devices.
Spent most of today getting 3 skylights to "learn" thier range of motion... Homeworks, Crestron, and several weather sensors.
Anyway, Homeworks, Crestron, AMX and Litetouch are some of the bigger names in over-control of things. Personaly doing whole house systems like that is a great way for people to feel like they spent enough money. If they spent less how would they ever compare to the Jones'. But for the most part its lights and occassionaly window-shades... And usually way too much wire than it would take to do it simple switch style.
However I do day dream of having the dinning room table convert to a pool table, all the cabinets flip to expose a bar, and start James Browns "It's Mans World" at the touch of a button.....