NaH20, here is a shot of the canopy I ended up putting together:
It's just a frame made with 1x2's and a bunch of screws. I have some eyes screwed into the top and some 'S' hooks to hook to the chain, and that's about it. I put the ballasts on the back of the frame, which made it back-heavy, so I balanced it out by taping a rock to the front. I need to neaten up all the wires and get them running along the frame, but I just haven't had time.
If I did it again, I would try to rig some sort of pulley system or something where I could just pull a chord and the entire thing easily went up. I have it high enough over the tank so I can stick my arm in there, but if I ever need to do anything major, I just unhook the 'S' hooks and hook them to a higher part on the chain, raising the front part of the frame. It's not hard, but a bit of a pain sometimes.
It definitely won't win any contests, but it is definitely functional! There is no heat to worry about being added to the tank, either, because it's so open.