If someone has a chance, it would be helpful to run the client on a machine that is monitored for traffic and connection volume. At least count SYNs to the bitcoin port. Ideally, use the IP for nothing else for awhile and log *all* traffic to it to see if you get probes, attack attempts, and the like. Post your summarized statistical results so we can have a baseline for what's normal. If nobody else does this, I'll try to do it myself tomorrow sometime.
Would be quite helpful if somebody(s) set up several honeypots and left them connected to the network, reporting the results periodically. There are downloadable honeypot configurations that should make this easy enough.