I still suck at using Sketchup (but haven't put POVRay and Moray on the new computer yet) but ... thoughts?
This version is 6x8, 4' tall in the front and 5' in the rear, I'm thinking about shrinking it down to 5'8x8 or even 5x8. If I go down to 5x8, I'll have to put the bed lengthwise instead of across, though.
Mostly inspired by the Stewart Family's weekender.

And yes, the front section is a 'skylight' but I do not think I would actually do that, even though it looks cool - someone has a Lexan roof in the gallery but that seems sort of complicated and I'd worry about hail.