I could have sworn bitbucket was an SVN host to start with, then patched in mercurial support and then git support later.

Bitbucket never supported svn (and still doesn't), it was created with django + uses the pure python mercurial (It was one of the major "posterchild" stories for django).

Not sure if it's still django though.

You might be thinking of http://beanstalkapp.com/ which supports svn.

Just re-read the original announcement, it was definitely a mercurial only hosting.

> Over the past couple of months, I've been working on creating a simple but powerful hosting service for Mercurial.

And there is also https://rhodecode.com/