http://www.minecraftforum.net/topic/682246-181-golem-mod-v20-mob/ (Updated more frequently)

After seeing this post on reddit:
www.reddit.com/r/Minecraft/comments/knc0b/suggestion_craft_pistons_and_a_suit_of_armor_to/
I have begun learning how to mod in order to make it so!
Currently I've got the golem and a battery craftable, when you right click the ground it spawns the golem. when you right click the golem it brings up a menu where you can give him a small set of equipment, the item on the far left is equiped in his hand. When a golem dies, it drops a depleted battery which can be recharged, and 1-5 pieces of coal.

Current Status:

A golem is craftable, first crafting a battery then the golem.
Right clicking with the golem item uses it up and spawns a golem.
Right clicking on a golem opens up a menu where you can equip 3 items, coal, a repair hammer, and give him commands.
While not in his "stand" state, the golem will use coal like a furnace but at a much slower pace. Currently 64 coal gives about 55 minutes of golem use. When he runs out of coal, he behaves the same as his "stand" state.
If there is a repair hammer in his inventory, he will automatically heal. Better materials have more uses (same as other tools of the same material) and heal quicker, wood is the slowest followed by stone, then iron, diamond, and gold.
Follow means the Golem will follow you and protect you.
Guard means the Golem will stand still and attack enemies that get too close to him.
Patrol means the Golem will follow a redstone path and attack enemies that get too close to him.
Stand means the Golem will stand still, doing nothing, and using no power.
The golem can attack with a sword or bow (provided he has at least 1 arrow), using the weapon farthest to the right in his inventory (ie: he will switch to the next weapon when his current breaks)

Plans for updates:

Better redstone pathing (move up and down blocks)
Different types of golems made from other armor/materials:
Wood/stone golem: used for harvesting trees or ore
Gold golem: returns to a recharging station when low on power, no more reliance on coal!
Leather golem: kills friendly mobs?
Diamond golem: stands there like a boss, possibly collects your items when you die
Add strafing to his bow fighting abilities
An smp version that will be able to attack players who didn't craft it (will have to have a marker to designate who the owner is)
Hitting it with a repair hammer heals it
particle effects when in action (smoke/fire for the coal fueled ones and redstone for the golden ones)

Ideas for enhancement:

A "backpack" where he can hold miscelaneous items that you give/throw to him (like a pack mule)
Possibly a way to give him a pick and he will mine with/for you (ideas include: he mines whatever ore you are mining, you give him an ore and he mines that ore)
Possibility for incorrect behavior when low on energy/fuel (attacks you if you hurt it, picks up/places blocks as per enderman)

Other videos:

Basic video:
www.youtube.com/watch?v=oyHD7m1ylvk

Menu and that he can hold items:
www.youtube.com/watch?v=QVNonT5w3hg

Coal usage and the state change button
www.youtube.com/watch?v=5hABzCXBh24

Repair hammers!
www.youtube.com/watch?v=nBE3ktuKuO0

We have movement!
[media]www.youtube.com/watch?v=-hVssMiBOH0

(I meant to upload this here earlier but kept forgetting to ^^;, also the video was made by GameChap on youtube and I do not claim it as my own work, merely the mod they showed off)