This looks ok in artifact file names, but what about JIRA version numbers? Will we use full version qualifier strings or shorter naming scheme, e.g. 4.0.0.M1?
This really breaks down into computer friendly with timestamp ( for mvn, osgi, etc... ), and person friendly.
We only need to use computer friendly where the computers need to care ( pom files, directory names for docs, svn tags, etc...)
NOTE: The timestamp is the date of the tag, not release
For other places I think we should just use 4.0.0.M1 format. "Milestone" is too long and I don't think that anyone would be confused.