no reason not to do it as long as you stay within teh rating of the transformer.

Thanks - I suppose it's no different from houses being fed from a substation, I just wanted to run it past someone :)

It is different from houses being fed from a substation.

For one it is different equipment, that may or may not be manufactured to perform with multiple loads.

Unless the equipment is intended for multiple taps(will have multiple lugs for connection) adding an additional load may void the warranty and create liabilities.

I think you misread my question. The substation analogy was a crude one.

Sure, there are some multitap transformers that are probably ok to supply more than one voltage (the transformers in hi-fi amps for one) and some that are probably not. Some multitap transformers can supply a larger current on one tap, and less on another, again I guess an amplifier is a good example, as you will need a small amount of current, which will be rectified and probably regulated, to drive the preamp, whereas you will need a second supply, again rectified but almost definitely not regulated (unless it's a honking big one or used in conjunction with a power transistor or two) which will drive the power amp. I am talking about a simple transformer, basically a higher capacity alarm transformer (they're usually secondary 16.5vac) that would normally feed 16.5vac to just one panel, my query was, could you drive a second device from the same transformer provided you didn't exceed the load rating.