The lifetag system is pretty good. No GPS but then,, if you have a strobe and the alarm goes off when someone falls off you can easily find them from the MOB position it leaves behind. Of course the strobe would be an extra.

If you're only having one person awake at night then purchase a small waterproof handheld that you can attach to the self inflating harness the crewmember would be wearing. With a lifetag/VHF & strobe along with a tethering in to the cockpit rule when alone you're covered. No one will fall overboard. For peeing, get a HERE bottle and make it mandatory to use in the cockpit.

If you have an SSB set up for email, set up an account with 'Posterous' (posterous.com). I sent the following updates to the page via SSB email (including the photo www.svtropicaldance.posterous.com ). Your son can transmit updates to a page with photos while at the same time sending out emails to his friends for the project. Hell,, he has to spend a bit of time for the project. If your updates are automatic then where's the project?

I think you're making too big a deal of the overboard thing. With proper rules a crewmember won't fall off while others are asleep.