alternate fuel tank question

[Painter D]

so the rear mount gas tank that lmc sells seems like it will hang down too low for what i need.my truck is lowered right now, but im going to bag it later this winter, and make it lay frame.so my question is does anyone make a different tank that will mount in the rear and fit there nicely without hanging too low? pics would be helpful . im also not going to raise my whole bed floor so space is limited. also ,how do you post pics on this site?