Yeap GRJ, so far I use a seperate feed from my xformer accessory connection for any AC voltages required in the 12-18VAC range. Right now everything I have that takes AC operates in the 12-15VAC ranges. I have found that 12VAC runs about everything I have in the AC requirements bucket. As I add AC accessories if I find that I need significantly varying AC voltages, I'll address it then.
My goal is to figure out how to run/wire all my DC accessories to operate off a single ATX power supply. The challenge of course is the 3VDC, 4.5VDC, 6VDC, 9VDC and 12VDC variations between lights, and animated accessories running into a fuse box then power distribution buss. And then of course there's the AMP math. Between house wiring, boat wiring and layout wiring, it seems I spend more time thinking about amps than anything else.