You'll find 1, just check around and check on the car-part.com site it is very good for locating parts, but still look around at your local yards. I've been to many yards and the people working there don't have much a clue as to what they have in their yards. I found 2 XJ dana 44 axles that they didn't know they had. I picked 1 up for $300 and found 1 at the local pnp for $130. $400 isn't a bad price, I'd get it of keep looking, but don't expect to get it much lower than $400. This is a bolt in beefy stock XJ axle so it is priced according to that. If you don't mind doing some modifications then get a ford 8.8, dana 60, ford 9" etc, but this is a bolt in axle so it isn't going to be cheap. Just don't bring much attention to it at the yard when/if you find 1 and see if you can get some $ by bringing them your dana 35 or 8.25 I wish you the best. I see XJ 44's alot on ebay in the Eastern PA area, a guy has them on there all the time. I'm sure you will also see them in the metro NY/NJ areas, just clean up the rust and rebuild it.
Troy