Yes, that would be an option if my work allowed any services like that(and yes, it's slightly odd that dropbox/google drive are not allowed, but Steam cloud sync is).

Not sure if it helps any, but box.net allows webdav access and can be mounted natively by Windows.

Oh but it's not a technical issue - both dropbox and google drive would install and work fine, we have full administrative access on our machines with no restrictions. But it is against policy.