Bitcasa has finally released a desktop client for Linux users.
The app is currently in testing stage though you can download and start using it.
It requires Qt.
1. Paths beginning with /media are not allowed (fixing very soon)
Supported distributions (so far):
1. Ubuntu 11.10 (oneiric) or 12.04 (precise) with KDE, Gnome or Unity desktop. 64-bit only