Well Im a little late to the fun here at naxja, but we're driving on the same trail it seems.
my 94 "xJ" ( I'm learning fast ), we call it a Cherokee here in new mexico
has the same rusted out tank and the same fuel pump issue as you. Ugh, i'm just getting ready to retire and I have to deal with a crap job like this because I'd take a real ass beating if I tried to sell the xj needing this work
i decided to pull the tank after I found it nearly impossible to get the pump and gasket in place and get the lock ring started without the car on a lift, and even then it was a reach. and the tank was pretty scummy too.
Turn out the tank was also rusted, after all it is really old, and mine has been sitting for several years with a nearly empty tank.
so why unobtainum?..several reasons but for us its two things as you've noted
1-our regulator is on the fuel rail, we have a return hose. looks like as stated previous that stopped in 96, the aftermarket seems confused about this particular point
2-the fuel gauge may not read correctly if you use a pump hanger from a 93 or early, however, I suspect they fit into the tank just fine. The ohm-age of the 94 might be significantly different. I'm sure you've seen the listing that indicates this spec for the 91-93 side mount pump fuel senders
Ohm range: Full 100-115, Empty 0-5.
and to think I hated top of the tank mounted pumps...I cut a hole in the floorboards to access one if I could just order up the right stuff. at least the tanks are not wallet busters. I'm going to pay a little extra (+$40) and pick up one in town, I can't deal with returning any more stuff this month, its tiring
any thoughts on going with an external pump?
I'd be so bold as to ask you to check the fuel sender operation before you actually stick that pump in the tank
I'm pretty confident I can get around the ohm range issue...maybe
looking forward to hearing about your new pump.