Sounds interesting; I hadn't heard of PCem before. Does it always require a BIOS image from an original computer, though? Or are those just for some potential machine-specific functionality or something? The table of emulated systems lists ROM image file names, yet no ROM images are included (of course, as they're under copyright and proprietary).

The ROMs are one Google search away, on a public Github.

Yeah, I don't doubt the ROMs can be found. It's nevertheless an additional step to take over just throwing DOSBox[-X] at the problem, though.

Still, an ambitious project.