I run an Isuzu D44 rear, so does Powerman. Interesting question on whether an XJ D44 shaft might work, in that since the I44 is narrower than the XJ, and has equal length shafts, its possible that the shortside shaft on an XJ D44 might be close to the right length - if anyone has a measurement, I can compare it to my I44 spare tonight...
That said, the bearing retainers on the I44 axle are really different from most rear D44's, so I don't know if that could be overcome or not. No doubt you could redrill the I44 rotors to 5 on 4.5 if everything else worked...