Have you tried Industrial Craft? It's a complicated 'tier 2' mod created by Alblaka. It adds new ores and machines to the game. He currently made a SMP version but when asked about bukkit, he says that someone can do it if they want. So, I just wanted to see if there is a modder here that wants a challenge! http://www.minecraftforum.net/viewtopic.php?f=1032&t=199635
Ahhh, see I don't know anything about modding.Thank you for responding. Tier 2 is how he describes it. A lot of mods as soon as you install it, it starts changing something, doing something. IC takes alot of work and planning to start building machines.