Well, besides the kickstart replacement there is also going to be AROS 68K, which technically is a hobbyist 68K OS "workalike" to OS3.1 - but not actually based on OS3.1, instead written from the ground up.
Wasn't there also a workbench desktop replacement out there --- can't remember what it was called now. Oh yes: Scalos (
http://scalos.noname.fr/). A partial hobbyist OS, anyway.
