Thanks for the info Bill and Phil :)  It ties in with what I
thought, so I'll go back to evaluating the original idea of
a wooden case as Phil suggests (I thought the plastic might
be easier, but withthe grounding perhaps not).

Cheers, Paul

Bill:
Several things come to mind. Most plastics will readily
acquire static charges, so I think that bare plastic is
probably a bad idea. If you really want to use the tub, I
might suggest a shielding layer like metal foil
spray-mounted to the inside of the tub. This shield should
be made
common to the ground side of the supply (and motherboard as
well, if possible). This also will help with RFI issues,
which could show up at any point.
--__--__--

Phil:
Oh, and I thought you were talking about some kind of nice
hardwood thing.  If a plastic storage tub blends into the
decor of your living room, are you sure it's worth the
trouble? :)