Sounds like you want something along the lines of libretro. It's an API and reference implementation (Retroarch) for emulator "cores" to interface with a stand

Sounds like you want something along the lines of libretro. It's an API and reference implementation (Retroarch) for emulator "cores" to interface with a standard front end which handles inputs, UI, and other things. MAME/MESS and many other popular emulators have been ported to libretro, as has Doom via prboom