OK, been there, done that. SkySlab had a swivelling flat roof system (due to space limits) but it proved to be hard to secure and a little difficult to open and balance. It finally blew off into the neighbours backyard (twice!) and I replaced it with my own split roof system Essentially a pair of sloped roof sections that meet slightly offset from the middle and just slide along the top edge of the shed walls. I made it from exterior ply and some 150 x 25 x 1800 fencing timber plus a lot of self tapping screws ( love my battery power drill driver ). I'll find\take some pix if you like so you get the idea. It is quite light.
Here a pic of it in another thread
http://www.iceinspace.com.au/forum/s...d.php?t=123058
Skyslab is 2.65 x 1.75, a bit smaller than your idea. A nice feature I hadn't realised was the abilty to just open a sufficient gap for a particular target and thus reduce dew and protect PC's and other equipment.
I think you'll find Scopes and stuff take up a lot more room than you think and the tools might get relegated elsewhere
... just saying...