Hmm... could do the piano bench type hinge at a little off-center toward the front but the lights are retrofitted onto a solid piece of metal. So it would require cutting through that as well. Also, the electrical cords that go to the front lights... not enough give.
As for the pulley, it's a great idea, except that the main point of this is to avoid drilling holes in my wall or ceiling, lol! Maybe as a last resort.
I'm liking the idea of the hatchback hinges... thinking about checking out a junkyard. I'm not quite sure how long they are... no hatchbacks convenient for me to eyeball. Wondering how long they are and how much space they'd require. And, of course, how much force would be required to close them and how to keep them closed!

Lots of "ifs".
Meanwhile, thanks for the brainstorming and the kind welcomes (and thanks to my sweetheart for posting the pics of the tank and canopy)! Absolutely love the site!