We use BitBucket together with JIRA OnDemand, and when we set up a repository tied to a project in JIRA we always name the repository the same as the JIRA //project key//.
We imported some of our old subversion repositories, and realized after it was too late that the repositories had been named in all-lowercase letters. We tried to fix this by changing the name of the repository to all-caps, but the change does not go through. I guess this is because the name is case insensitive.
It seems possible to work around this issue by renaming in two steps.