Does there exist a firefox.tar.bz2 package for Raspi (!ARM!) which can be downloaded? (Making firefox "portable" on Raspi)
I have a tip for you that might work.
You can start firefox like this:
firefox --profile /path/to/profile
Interestingly, you can also just use:
firefox --profile .
Where . tells it to use the current directory as the profile. That way, if it was on a USB drive for example, it would be portable, as long as you launched it that way. All the data would be tied to the current directory where it was launched from.