Have you checked through every nook and corner of
Aminet? I seem to recall (although I admit that I haven't
actively looked specifically for it) the term 'MUD' appearing
numerous times.
I remember because I didn't know what it was and had to
load the readme:s ('mud' sounding kinda odd if you don't
know what it stands for).
I'm sure you can find some included sources to peek at if
you look long and hard enough.
.
SlimJim