Why Mirrodin's Core? It doesn't do anything for the deck. I'd much rather run Urborg (let's your pain lands tap without hitting you) or Haven of the Spirit Dragon (recurs Ugin or Steel Hellkite).

Mirrodin's Core was me just mis-reading it. I'll swap it out. I didn't think of Haven of the Spirit Dragon , cheers.

I've been running Karn, Silver Golem as a commander deck for a while now and I think there's some cards you should run too if you're going into the colorless strategy

• Voltaic Key: It does so many things. The big thing is turning your mana rocks into extra mana. It becomes incredibly powerful with Basalt Monolith, Grim Monolith, or Mana Vault. Otherwise it gives your artifact creatuers pseudo-vigilance or reuses any tap ability (just off your list, Quicksilver Amulet and Staff of Nin at a glance).
• Null Brooch: This card is awesome. Colorless decks dump their hands quickly and are vulnerable to a ton of noncreature spells (mainly mass artifact removal). Null Brooch is one of the only counterspells in your (lack of) colors. I've created some serious lockdowns with Null Brooch and Unwinding Clock. Plus, I'd much rather ditch a decent hand to stop a Merciless Eviction than be blown so far out of the game that I can't recover.
• Soul of New Phyrexia: Great beater, amazing ability, it'll save your ass so many times. Especially since Darksteel Forge doesn't protect your Eldrazi, it becomes a very useful tool for saving some of your more notable colorless permanents.
• Mana Vault: It's a couple of bucks but it's worth it. Allows for some of the most explosive turn one plays. I've done everything from drop it into a Worn Powerstone to drop it into a Voltaic Key, into a Thran Dynamo, into a Sculpting Steel as a Thran Dynamo, all on turn one. You can get one for <$10 easily and it's part of that trifecta of broken fast mana with Sol Ring, Grim Monolith, and Mana Crypt.

Mirrorworks

Any thought on Sensei's Divining Top? Other than the obvious perks it turns into infinite draw with any of your infinite Rings of Brighthearth combos and works well with Paradox Engine, going infinite if you have a second source of draw and a rock or two on the board.