Just throwing my 2¢ in on this one. Although a good idea, we didn't see a lot of users on a steady basis on the PVP servers which led to their eventual and understandable closing.
If we were to implement this, would we not isolate those weekend gamers who want to play PVE only and are only available on weekends and they will end up not to not wanting to play the server at all or less then they do/can already? I've been playing on the PVE server for a while now and mainly play on weekends as my work carries into the night most weekdays. The PVE element is what I enjoy playing, taking that away for the bulk of the time I have free would limit how often I log in to the server, I'm sure they may be some others with me on this one.
What would be cool is to have a separate area for PVP only. Anything lost in there is fair game, if you want to roam the specified area (a walled off city perhaps) then it shouldn't matter what gear you loose or vics taken because its your choice to enter the area. Also remove the humanity minus effect if possible...anyone who PVPs outside this zone can be banned anyway.
I'm all for a monthly event or something similar but every weekend may do more damage then good to the existing players.