I could probably get the rom for the super gameboy cartridge. But does anyone think there would be any way to load a game boy rom along with that rom?
No. Super Gameboy contains full Gameboy hardware including a 4.19 MHz Z80/8080 CPU. Neither Snes nor Everdrive have the cpu power or logic gates to emulate a CPU. When Super Gameboy is running on SNES, all Gameboy stuff runs on Super Gameboy, all SNES does is sit idle and copy the final screen data and process controller input. A CPU needs to be at least 10x more powerful than CPU its emulating and you need lots of RAM. No way a 65816 @ 3.58 MHz with 128k can emulate a Gameboy CPU let alone the video/audio functions.