I've been investigating some of the unused and testpoints on the DTL-H2000 and decided to drop the info here:
Whilst the external serial and AV ports are non-playstation in design, the board happens to have a properly-ordered set of unpopulated pins at J801 and J806 for connecting the Playstation style MultiAV and Link ports:
Another nice feature of the board (for crazy people like myself) are the testpoints for 3.3v(approximate), +5V, -5V, and +5V Digital, as well as their associated grounds.
The -5V should allow for the easy incorporation of a simple RGB to Component circuit without the need for an external power supply.
Hope this is of use to someone- I'll try to determine what the other ports relate to on here later on.