It may not look very elegant but how about prefixing the mutator name with the original creation (or perhaps current release) date? Like for example:
That way at least it's very unlikely that someone will make a package with the same name on the exact same date you decide to make one.
It also means that you know a) how long the mod has been going (if you use the original date) or b) how recent your version is.
I agree, I think I will do this ^^