to get the dent out you can use air pressure to get most of it out. but since your going to Kreem the tank any way, just fashion a "L" bar out of some stiff steel, and work the dent out from the inside as best you can and bondo the rest. I had a 350X tank that was repaired using air and it came out GREAT! ... see the before and afters below
http://i112.photobucket.com/albums/n194/yo...es/DSC04468.jpg
http://i112.photobucket.com/albums/n194/yo...es/DSC04473.jpg
http://i112.photobucket.com/albums/n194/yo...es/100_0122.jpg
http://i112.photobucket.com/albums/n194/yo...es/100_0135.jpg
http://i112.photobucket.com/albums/n194/yo...es/100_0133.jpg
FYI, this is also a good source for other parts and trick stuff that you might be interested in!
http://www.sterdyproducts.com/productcart/pc/viewCat.asp