Ok, I talked to Steve at ARB. Basically they have had axles in Australia since 05.

His comments were....

1. They have not seriously looked at anything yet.
2. The differentials for the Titan, X and Frontier are so poorly and under-engineered THEY are concerned about working with them!
3. They were worried about over heating of the D44.(I explained I thought this was an issue fixed in 05 with the bigger cover on the Titan, but I couldnt confirm that was what he was talking about)