Since you've mentioned that you ditch/replace your tents every few years, could you simply take a razor, cut the top of the tent out (a hole in the top of the tent essentially), move the tent out of the way, staple some mylar/panda to the ceiling, build a 2x2" box frame of sorts attached to the ceiling, about 1" above the height of your current tent, slide the tent under the framing, then drop the mylar/panda down over the sides of the tent, tape it up, and call it a day?
Am I being clear on what I'm thinking?