side mount gas tank

[jyukon]

I have a 66 Chevy fleetside shortbed that was converted to a 4x4. I want to move the fuel tank out of the cab but also want to keep the spare under the rear. Has anyone moved the tank under the bed in front of the rear axle between the frame and the driveshaft? I have read many threads about the rear mount tanks but haven't seen any about the side mount inside the frame. Is a custom tank the only way to go? I need to be able to stick with the 0-30 ohm sender also.
Thanks for your input.