The LJ and moving it forward a bit should give a lot of transfer case options. I really like the idea of a doubler with something like a 4:1 Dana 300 and NP 231, kind of a best of both worlds setup. Not sure it's worth it for most people, but I love selecting the exact gearing I want. Might be a lot of work getting the shifter to shift correctly on the transmission though if it's forward.
I love the TDI Jeeps. It's what got me really looking at TJs. Looking back, I probably would have gone LJ, but it has yet to be an issue either. The wife seemed to like the idea of doing a TDI buggy, so I may figure out one of those one day. I just love those little engines, but so often I need to tow and just need a much bigger engine, even compared to my 2.8.
Just to let you know, the 2in thickness is just enough for firewall clearance on the ALH. I think I only had 1/2" to 3/4" between the firewall and vacuum pump. This would be minimum clearance for the vacumm pump removal.