Decided to use my friend's idea ConnLock.

I haven't uploaded it to extras-devel, because I want to fix couple things first, but here is .deb:
http://hosted.laasonen.net/connlock_0.1.0-1_all.deb

There is something really strange about osso-systemui. Power button menu randomly stops working. I first thought it was just my shell script which was directly reading pwrbutton, but it's now happening with my python/dbus version Is it just me? Any suggestions?