One of the hardware designers of the alphatronic P2 has a website with loads of information on that machine, his role in its genesis and the family tree of the SKS machines.http://www.waltroper-aufbruch.de/Archiv/AlphatronicP2.php
He also offers the P2's BIOS ROMs for download, unfortunately his Eprom programmer can't read the P2's TMS2716 chargen ROM.
In its place he suggested to use the ITT3030's 2KB chargen ROM and he sent me the NANO 2500's chargen ROM - which turned out to be identical.
If you drop the P3 chargen into the ITT3030 driver, the ITT suddenly remembers its German provenience and starts to show Umlauts
and the shape of the characters is different, but doesn't complain otherwise.
MAME ITT3030 with original chargen ROM
MAME ITT3030 with alphatronic P3 chargen ROM
Maybe the P3's ROM could be used for an upcoming P2 driver as a "BAD DUMP" until the P2's gets dumped.
The P2 is interesting in that there are two flavours of CP/M, one that has its TPA at the common 0x0100 address, the other at 0x4300.
This guy published high quality pictures of his P2's cards:http://petersieg.bplaced.net/?8085:Alphatronic_P1%2F2