It looks as if the lightest (known) road bike out there right now weighs in at about six pounds. It is not particularly fragile -- the original owner put something like 20,000 kilometers on it, and it's still good to go.

However [and this is the real deal killer for me, at the moment at least, and probably forever as well, no matter how much more money I have] -- it will cost at least 45k USDs to duplicate the effort.

http://www.antranik.org/worlds-light...bike-at-2-7kg/

For 100k, you might be able to get down to five pounds. Maybe even lower. A four-point-something pound bike. Awesome.

The money might not be totally wasted either -- at least you would be supporting some [mentally challenged obsessives?] [perfectly normal guys interested in pushing the limits?] [meaninglessly frittering away their lives] [or not].