The other day I did an SVN commit from textmate.
In the commit message window I pasted in some text I'd copied from a message from a client from BaseCamp.
When I tried to commit, it failed complaining about mixed line endings (paraphrasing from memory).
It seems to me that this is something that the subversion bundle could sanitize.
I tried to figure out how to patch this, but I think that this is all handled within the internal CommitWindow.app which I can't (or don't know how to) look at.