XULRunner Portable

This seems like it shouldn't be too difficult to make portable. I'd very much like to not have to use FireFTP and ChatZilla via Firefox(because it takes a long time to load up on my portable drive -- I'm blaming the USB1.1 interface at work on that), and XULRunner seems to be the answer to that, but it makes entries in the registry and I don't know the first thing about making an app portable. If this has already been done and I somehow missed it in my search, I'd be glad for a shove in the right direction.