First off, the board itself isn't very common to find because of the fact only one known game uses this board (I'm sure some of you will figure out soon). Aside from the fact nobody else mentioned this board, the hardware this board consists of is rather interesting for what Taito developed. The board itself sits on top of the FC pcb.
Specs:
H8/3062 HD64F3062F CPU; clock not known; has an internal rom yet to be dumped.
IDT7024 4k x 16 bit dual port ram; most likely shared ram between the G-Net board and communications cpu
SMSC COM2002ILJP Arcnet controller w/2k x 8 bit ram...