In terms of a network share, just run two Crashplans? One on the device with the network share and one on the backup client. Not ideal given it all runs in Java (still).
The way I understood it, he wants the computer to be backed up TO the network share, not back up the network share its self. I read it as the data was living on his computer primarily, not the share. Your solution is the one I'm currently using. Actually, I don't even have Crashplan installed on my desktop because I don't keep anything on it that I care about.