I thought I'd read something about some JB install that would allow you to mount the filesystem as a drive, but I don't know how it works. I've got SSH active for use with the filesystem and currently I'm happy with SFTP over WiFi.

I did just find one program "USB Drive" which allows you to create virtual drives that work as mass storage, but I don't think it shows the rest of the filesystem. It's not the program I'd read about before.