Plain ol' 1/16" sheet metal will work just fine; however you're going to run into several problems...
Holes can be cut relatively easy with bi-metal drill bits; however, these can be rather expensive and do get dull.
Angled cuts as well as any folding and shaping of the panel will be very difficult. You're only reasonable option, IMHO, is to contact your local machine shop to see if they'll fabricate a piece based on your specifications. You'll pay quite a bit on this, but the tools you'd need for anything but a rudimentary panel would probably be more expensive....
As for finishing, standard contact paper would work, on which you could decorate. Happs sells CP laminate, too - that would also work just fine.