It is not just a rom. I have seen the actual cart in Hong Kong and Tokyo. There is really only one guy in tokyo who makes and sells these things. He is also responsible for the pokemon and donkey kong country carts. But the others, like tekken, are mostly graphic hacks... I have picked up a few including a pong and omega race cart made in korea but authored by some finnish guy using commodore vic-20 roms! strange but true! I emailed him and he said he had made the rom in 92 but didn't know someone was making carts out of it.
