I genned a few worlds looking for one with a decent mix of biomes with snow on part of it, and I think I've settled on this one:
The server seems to be working OK so far from my testing (at least with just me on it), and the automatic hourly world backup and map image generation is mostly worked out with just a few more details to handle. Each time it runs that, it overwrites the "current" world map image which will be displayed on the website. I've been having trouble getting PHP hooked up to access the Minecraft server commands and info, but I'm continuing to fiddle with that as well.
I'll probably be running hMod or maybe the Hudson offshoot of that for the additional options and admin commands. I'll leave the server open to the public initially, but if there's too much griefing I can switch to using a whitelist and just add people as they request access.
Another day or two and I should be ready to open it.
How about some sort of organized pvp? Griefing and stealing would be forbidden of course, but you could allow people to "challenge" other players/teams in battle, claiming their property afterwards (so you could burn enemy castles to the ground after you've taken them, as griefing your "own" stuff is allowed , maybe with the exception of certain creations --> "cultural heritage" )