Sorry for barging in here, but I found the thread while trying to do just that, so.. :-)
Anyway, I have several projects on my local computer, all with local svn repositories. Lo and behold, my wireless lan card busts and HP wants the computer for repairs (No charge btw.. really very nice of them!) This means that I have had to migrate my entire dev-environment to a different machine.
For various reasons I cannot simply reformat this machine; I need it as-is. Unfortunately all my SCM entries are using a file:/// url, not a http:// one, and now all my repositories are in D:\repos instead of C:\Users\Public\repos. Of necessity, btw. There is scant space on drive C.
Of course, I could just delete the SCM entry and restart; however, several of those repositories are mirrors of large projects, and I would hate having to wait for the fetch_changesets method to complete again... It took a day and some last time, and I migrated to an older - and slower - computer.
So, what I was hoping to get from this feature, to answer your question, is to change the path to the repository, without losing the changesets already fetched. Yes, it can be worked around. No, I really don't want to!
I'll go hacking through the db file now instead. :-) Where should I look? :-D