While we like our bikes to be all shiny and scratch free and immaculate, I realize they are just tools to get us from Point A to Point B, just like any other conveyance. I learned this lesson a long while ago. Sooner or later, they're going to get scratched, or dented, or dirty, or wrecked. Next new car I get, I'm going to take my best hammer, and put the first dent in it myself.
I agree: if there's no crease in the sheetmetal, you may be able to pop it out with either the heat/dry_ice method, the paintless dent wizard people, or possibly sealing the tank and using a bit of compressed air. Sometimes they'll pop out with a little pressure and some tapping with a mallet.
Good luck, and let us know how it goes.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.