I dunno about the shaft for the jrx-s. I'm sure they considered a shaft at some point, but they obviuosly discarded it.
In regards to the original question:
If losi just convert the jrx-s to off-road, then it'll be the first losi 4wd off-road car I won't
be buying. IMO the diffs are WAY to exposed to have a realistic lifespand before a rebuild is necessary if you drive it on a outdoor dusty track, and the suspension is way to short to be effective on any type of off-road track.
I would like to see a center battery mounting position, but I'm not sure they'll put that much work into it. I'd imagine we'll see an overall layout similar to the xx4, but with easier access to the drivetrain.
IMO that is...