Originally Posted by abshipp

I don't think it would actually be terribly difficult to do - at least physically making the parts. The Rohloff uses a carrier for the cog and freehub body geometry is well defined so you'd just have to combine the two, plus a longer axle and you'd be pretty much there. I think the biggest concern would be axle strength since if you just made the axle longer you'd have a long unsupported length outboard of the bearings.

Plus you may need to use fat bike rear spacing to get it all to fit and chainline might end up being a mess