I apologize for the difficulty of finding contact information. We try to do most dealings via GitHub which we know doesn't work for everyone.
This would work as a solution except for that we would then break updates for current users in the same way that it would break if someone stopped using MELPA. It is also not clear in this case how to handle packages that don't include a version number.
I'm happy to keep this discussion open as I know it affects many users as well as developers.
One solution I might suggest is the approach that js2-mode has taken on the GNU repo. It seems that their versions follow with MELPA sans the time. I think that having arbitrary version numbers for things like extensions is a little overkill and MELPA is at least a little evidence that versioning based in the date of release *can* work. In this case it could be as simple as the Emacs community endorsing a release date based versioning system.