I believe BoKus high altitude sailplane was designed like that.The year before last I had my first Sailplane ride. It was great other than I had a headache for several hours after the flight. This may have been for a couple different reasons or a combination or the two. This matter got me thinking along the lines of pressuring aircraft because I didn't want my ambitions to fly planes dashed. The matter may be a non-issue for me but regardless I think I may have thought of a pretty revolutionary way of pressuring a craft with very little weight and perhaps the best part is it would allow for aircraft shape non-conforming to pressurize standards (non-circular) cross-sections. Probably not actually revolutionary but it would simply be to build a pressure vessel separate from the airframe to house pilot/passengers. Would allow for more flexibility in design of aircraft hull shape as well as and perhaps most importantly un-coupling of other components such as wings or control surfaces and the need for robustness of design/materials in what would be these areas.