Ovis Canis
Observer
Don't really on the tape alone if it makes you feel uncomfortable. Put rivet in also, just wet install them with an epoxy. This is standard. I've built C5 galaxy replacement parts, G5's, Blackhawks and 747's. Completely normal.
I drilled and screwed my aluminum lid to the steel frame, with a bead of urethane caulk. Drilled the holes in the aluminum ever so slightly larger than the thread on the screws. Screwed roughly every 6" including down the middle. No warpage or screw head popping issues yet.
Why not build the frames out of aluminum also?
There is a long history of race cars built by riveting aluminum sheet to welded tube-steel frames. Take a look at every Lotus-7 and every Locost clone built in the last 50+ years. The issue of galvanic corrosion is overstated, at a minimum.
Yes, it is something that happens, but some basic precautions (such as painting the steel frame first) are really all that's needed.
For the OP, or anyone else considering such methods, I highly recommend you purchase or find at your local library a book called "Build your own race car for 250GBP"
(http://www.amazon.com/Build-Your-Sports-Little-£250/dp/1859606369)
The author extensively covers the techniques for sheeting aluminum over a tube-steel frame with rivets. More importantly for OP's application: He covers the process for annealing the sheet aluminum so that it can be successfully bent over a radius without cracking or tearing.
I wouldn't hesitate to take that approach. Paint the steel, and goop the rivets before seating them, and you'll be fine.