This is what I found on Audiocircle:
Hi,
We have been conservative on the HDP engineering and release, because it has to be perfect. We have changed the circuit architecture several times to add features, the aggregate functions and performance resulted in the HDP being a monster trying to go inside a small case, we have to break-down the circuit boards (multiple multi-layer circuit boards) stacking on each other just to fit the small chassis - which throws off the layout and circuit design schedule.
That said, we have been playing with the 1st cut of the final and working HDP, we have found a few bugs, and we are making the first production boards right now. So it's coming and getting very close.