Saw these advertised on TV and looked them up.
The Joey is just the right size for nice roll off roof or domed observatory.
http://www.shackinapack.com.au/range/the-joey.html , bit pricey for me but still , reduce the wall heights to just tall enough for the doors, put a pier in the middle and make the roof a roll off gable and it would be very nice as a home observatory.