Good post, fun read too.
When I bought my first "spinner" I posted here about trying to fix it, but never got anywhere. Then after some research on the subject I gave up... I believe without actually melting the iron and pressing it back into shape you will not be succesfull.
When the warp happens the iron is streched and causes the bulge part to be thinner than it previously was. THAT is the problem. You would have to compress the entire bulged surface back to its original thickness, not just whack it flat.
Reminds me of a 2x4. Lay a perfectly flat 2x4 on a cement floor... wait a few days (or overnight depending on the weather) and it will warp upward from the ends. Has to do with the exposed side staying dryer than the side against the cement, the moisture causes the cement side to expand, while the exposed side does not. Just you try to bend it back straight!
So I just gave all my spinners to freinds who have gas stovetops :)