To start off ill put forward my contributions, i being 17 / 18 years old and having little money
So to get my ride under the magic 5.00kg i took to it with a small range of power tools! Here goes:
Tuned Sram Red Rear Derailleur, 11 hours worth of work on it, final weight = 104.67 Grams. Saving of just over 40 grams. Have ridden over 5000km on it with no major failures (bar jockey wheels, see "AFC Pulley Wheel Review" Thread). Light and functional, and i think its pretty too... Plans to go under 95 Grams yet!
Tuned Sram Red Levers, 18 hours work in the pair, with continual research on hoods underway, waiting on some Clamps from Berk, Final weight will be under 210 Grams, originally weighed 298 Grams, so saving of around 90 Grams all up! Put 3000km on them with absolutely no worries at all!
Tuned Pedals that i will not say the name of (see "Tuned Pedals called PlaySpeed if you reversed the name..." thread for more info), 30 hours work in these, took a standard pair of Chromoly PlaySpeeds and took them down to 117.80 Grams from 208 Grams, 80 Grams gone, Handbuilt all of the alloy parts in it, and tuned the Ti axle, (boring and milling it), Second version plans are underway!
Custom Built Barrel adjuster and Nut, made out of Delrin, for the rear derailleur and down-tube adjuster as well, functions perfectly, and significantly lighter than what i've seen available for purchase here in NZ.
Home Made Areolite Pedals, on a Stainless Axle for my first Generation versions, have devised a system that can fit these to any existing axle (Titanium, Steel, Stanless... etc), Delrin barrels, lightest version i built (Stainless Steel Axle) = 65.6 Grams a pair!
I've also built ISP seat clamps and Toppers, my current version i ride now weighs a total of <20 Grams. All custom built Yokes, Thru Rod and Cradles! Pics to come!
Now Show me what you have all built! Hopefully im not the only one!!