Rear hub gears aren't warranted for DH use. Gboxx style units are a bit heavy. But, perhaps more importantly, they are bulky, so to use one would require the shock to be in a higher location or in front of the down-tube - as it was on the BCD Racing Coffin (back in '99 when they didn't know better!)

Having the shock low (as it is here) keeps the bike's COG low which really improves the handling and stability of a DH bike. (Note that most of the popular DH bikes at the moment have low shocks.) BTW, this pre-production model only weighs in at around 38lbs, with a tough Truetemper steel frame.

While a lightweight and compact hub or Gearbox set-up would be the ideal, they currently don't exist, so this seems to be the best solution for now. It has the excellent ground clearance of a Gearbox design (affording it a low BB height), and the chain system affords the design a high pivot point which gives the swing arm rearwards travel, which helps keep wheelbase from drastically shortening when landing big hits, and sucks up bumps much better than vertical and forward travel, typically seen on full suss'ers. High pivots went out of favour because pedalling issues, but this gearing design solves that problem.

This bike is the best DH bike I've seen (and read about - just check out Dirt Mag's October issue!)

Nah, doing O hole/window in the lower tube would get the shock in proper still low position. This would get enought clearance for some =5 geared hub. They know ho to work with steel, we all see that
Not sure how many they sell but I will wait for geared hub version