hammond enclosure. job done.
for a small, good looking, tough case for the pi Hammond make good plastic and aluminium enclosures, some of the aluminium cases are really nice, might need some remote ports though.. they do rugged steel instrument cases, and my favourite aluminium case with walnut side panels (expensive though)
I considered a metal case with a sloped side so a mini keyboard could be fitted there, as a go back to the old days where the keyboard was the whole computer
i agree though a 50g tobacco tin type size would make a versatile semiportable unit if the hammonds are too heavy or expensive
these are quite reasonably priced AFAIKhttp://www.hammondmfg.com/dwg8.htm