Gas tank relocation ideas

[6600DURAMAX]

I know this has been talked about but was wondering a couple specific things.

I am going to relocate my tank from behind the seat to simply gain more room and get the ugly filler neck moved. My ??? are what will work and be the coolest. I will have a fuel injected motor so I know I will need a return line and a tank with an intank fuel pump would be nice. What fits???

Can I rob a 88-up saddle tank and mount inside the frame or do I have to go the fuel cell route, and if that is the case is it alright to run poly tanks with fuel injection??

Oh ya, this is for my 72 4x4 conversion project.

thanks guys