It's possible

From Wikipedia page on Pokémon Stadium:
At the GB Tower, the player can play Pokémon Red, Blue, or Yellow on the Nintendo 64 using a Transfer Pak.

I was able to get this Game Boy game working by modifying the header of the game extensively and padding the game to 1MB. By using a Game Boy flash cartridge, the emulator thought the game was Pokémon Blue so therefore it booted it.

You need to login to view this link