Suggestions

[Xenol1997]

And idea that could work, would be if you had /fly, and too many items. Because you can configure servers to not allow certain items to be spawned (TNT/lava/water). The /fly command is a good idea, but doesnt get rid of the problem of having to spend ages going to and from spawn gathering items, not to mention the time it takes to break blocks :P My current build is a massive aircraft carrier made of iron, and the horror of having to break a load of iron blocks is a traumatising experience.

TMI is a client-side mod that basically runs the /give command in Multiplayer. People could easily give themselves large amounts of banned blocks, plus, they'd have to install it themselves, which from personal experience many people can't do. You can't actually configure servers to do that without a Bukkit plugin by the way, and this takes away from people who want to use water, lava and tnt in their builds (without abusing it). It doesn't take long to type /spawn and then /back, so I don't see the problem. If it takes you long to break blocks, go to spawn and get yourself a set of *free* diamond tools.

You can?! silly me! Ive been punching this iron all this time -_-

I dont pretend I know all the answers, perhaps if you spent as much time scalping my ideas as you did coming up with them, we could have solved this by now.
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Spent as much time scrapping is was I wanted to say*
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How about a separate creative server where only trusted members are whitelisted.