The dome is actually 3/4 inch metal conduit that has been cut to length, the ends have been hammered flat, drilled for hardware, and bent to approximately 16 to 18 degrees. It isn't overly complicated, but is WAY easier with a hydraulic press and drill press. Unfortunately I didn't have the access to the hydraulic press so I had to use a hammer an anvil to flatten the ends. The covering will just be greenhouse plastic sheeting. I may also look to use some reflective insulation in the interior at some point. The base and door framing will likely be pressure treated lumber. I would prefer the base to be metal, but lack of tools and materials can be limiting.
This website actually has some calculators in order to know how long each strut needs to be. The metal conduit framing is very strong, but can be bent if you really try to abuse it. Heavy loads (like myself) have to be distributed over several struts to keep them from damaging.
http://www.domerama.com