Incidentally, Storck now have an ~8.5 lbs (sub 4 kilo) or so roadbike out called Fascenario... it's made of standard, commercially available, non-tuned parts. You can actually order one of those things if you have the dough, they plan to make a small run of them! Frame is a Storck CF <800g job.
Crazy light bikes are all over the place.