Well, since you're asking, how about a Desktop-grade PS for a single unit? The current unit has six outputs, but I imagine 95% would use one or two devices. Maybe that wouldn't make it cheaper though.
Another non HR direct product would be a mail-in recabling of HD800 cables to converted to balanced (much like you do already with the 650 cable, but since the 800 cable is $$, many might like the conversion you've done there to their own 800 cables). This would lower the cost of getting into a balanced set, which would make your balanced products desirable. Why tie up cash when only a single set is needed? Sure, people wouldn't be able to return them with the mod, but they could buy a new stock cable if they really needed to. As far as I know, no one provides this service, and many won't want to hack it themselves.