I think that making Not enough items a plugin would be easier for servers. So if we could make Not Enough Items a plugin it would be great!!
actually, this could be made. DONT LOOSE HOPE! http://dev.bukkit.org/bukkit-plugins/createyourownmenus/ this one, I didn't make but bless the person who did. It lets you make custom menus and attach commands to items . So, in theory, you could make a Creative-ish menu full of /give blah blah blocks that could be acceded by a command or a block with the command tied to it.
I think he want's the crafting features. So he can like right click something and it will show how to craft it. This is possible but requires allot of work.
Madc0wz NEI uses a menu in the inventory on the right, this is just a chest menu. Unless you use Spout, which isn't supported here, you won't be able to do that. But if you just modify your CLIENT and you have OP / creative / permissions you are able to use NEI on the server. Jmac280 Reedalini
I agree with what Lionhard says. If you want to have the functionality of NEI then add it to your client through MinecraftForge. All of it's features are client sided including the recipes and such. There's even a way to change how it "gives" you items when you click on them (if you're an op of course)