Planned ruleset for the plugin-enabled edition of the server:

• All players get only one chest. From there, players cannot build chests, and ender chests. That one chest won't be protected, either. You can steal other players' chests. Use them wisely.
• Monsters will be alive both day and night. There will be plenty of them, so you better find shelter quick.
• Beds are almost useless. You cannot sleep through the night with them. Once you sleep in your bed, you set your home only once. Once you die, you wake up where your bed was. Your bed will be gone, so you cannot reuse it, and will have to build another one.
• Diamond utilities will be given a step down. You can enchant, but all tools except wood will last as long as stone tools.
• You can no longer level up by the default methods. You can level up by only killing monsters, or killing players. Somewhere along the way, a player will have a bounty, that will start high and decrease until the XP reward is near 0. This will motivate players to choose their allies wisely.
• Hiding is futile. All players will be equipped with a compass that will give them directions to nearest player, or at the cost of a few levels of XP, a player they want to attack. You better be prepared to run far and wide, and hope that nobody decides to after you.
• ...and much more!

This ruleset will weed out all players that want to play survival just to show off their e-peen with how many diamonds and how big of structures they make.

This is a server for only serious players with serious wants to play on a truly hardcore server. Yes, it will be painful, but the longer you survive, the better and better your chance gets at being #1 on the leaderboard! Who knows, there might eventually be real-world prizes.

Of course, that ruleset is not perfect, but it's something I'll start out with. Eventually, I will make amendments to the ruleset to perfect the hardcore survival experience.