This is not mine, but some impressive work, non the less with a dremel tool, some sheets of carbon and some pre-manufactured bolts. Sitting 114 grams. SICK!
Interesting - he used the now XTR design and took massive amounts of metal off this thing. I am not so sure about those carbon pully wheels. I wonder how they are side to side with the chain tension?
Here's a place to buy some good quality bike bolts/nuts/etc.
or
Here for some other tasty bike hardware.