I picked up a Summit fuel cell for the Scout. It had an ancient 2 tank setup that had long ago given up. I like the overall quality of the Summit, it was CAKE to hook up and has the safety foam and all that. I haven't come up with a very appealing mounting system though. Might see if I can steal any ideas from this thread as it grows
Frankly though, why do you want to ditch your stock tank Paul? I'm going to ditch the stocker on the CJ, but that's because I'm doing coils on the rear and stretching the wheelbase. The stock tank is in the way. This is ususally why you see fuel cells on moded CJs/YJs/TJs. I can't really think of a good reason to move it on a Wagoneer (assuming your mounting location is same as my 81) It's tucked up out of the way but as low as possible, helping out your COG. If you're beating up your stock skid plate, maybe beefing that up is a more fruitfull option. You're keeping a good size tank and you're keeping your weight down low by using the stocker. Maybe I'm missing something here but there really doesn't seem much to gain...asside from BLING of course
Anyway, just my $0.02.