Adjusting the testnet difficulty every, oh, say 100 blocks (instead of 2016) seems like a good idea to me.
That's a trivial patch; I nominate ArtForz and Xelister to write it and submit a pull request.
Locking in the testnet block chain-- not so much. I don't think it is worth the effort to either come up with a mechanism for distributing the lock-in points or manually put lock-in points in the source code.