That "crease" worries me too, but a body shop can probably make it good as new. I may try the dry ice trick since it probably will not hurt it any. Not holding my breath though.
My largest concern is getting the color right. I did find one on E-Bay, but it has a small dent with touch up with paint... I already have a dented tank and I could touch it up so I'm not jumping at that one. It hasn't been easy to find one that color, scrap yards included, but I'll keep at it.
May end up just buying a tank at $400(USD).