The DR-DOS/OpenDOS Enhancement Project

Another interesting sound card emulator for DOS was REMUS. I still remember that using it I could hear the sound of a GUS demo on an ISA SB compatible sound card which I owned in those times. AFAIK the last released version was 0.04g. Unfortunately the program isn't open source
(I think Roman Dolejsi wouldn't have nothing against to share the source code, of course in case he still has it, but even if he has lost it, with the disassemblers available today wouldn't be so complicated to see what the code does) and uses its own 32-bit PM manager, so it requires the CPU to be in real mode and consequently will not run under any VCPI/DPMI host.

Related link: http://cd.textfiles.com/darkdomain/programs/dos/emulators/remus04g.zip