So I had a friend show me this very interesting board. According to a few people (and the IPL rom data which seems to be talking to the Naomi CPU/GPU), it seems to be a rom development board for the Naomi. Knowing how rare anything Naomi development related is (if any has even been seen at all ), I thought this was very interesting. What you do is plop this on the Naomi, and then plop the Naomi cart on top of this if needed. Has a few inputs like SCSI, a couple of serials and some other SCSI type connection.
Neat piece. It looks like there are pretty much the same connections on it as a Katana (sans the A/V out and modem).