The weight requirement is 6.8kg. There are several mfg. of carbon fiber frames Cervelo, Trek, Giant, that can easily get bikes below this with a light enough wheelset and other light parts. I know a recent Trek design (SSLX) for Mtn. stages included brazeons at the base of the drop tube to add lead weights should it be deemed necessary by the UCI. I've also heard some speculation that a few riders have cheated by icing their frames for the weigh in, and then of course by the time they hit the ascents the ice has melted away to an illegal weight. They may have started doing weigh ins aferward now also, not sure.
Anyway the weight of the bike has become pretty much a moot factor in many ways. Even teams who are forced to use a technologically inferior frame can still drop down to the weight limit through the use of other lighter components (pedals, bars, stem, crank etc.) The rider himself is where weight is the largest consideration. Typically a bigger heavier rider will have more surface area which causes more drag, though they do often have a larger muscle mass. But, with more drag comes more resistance, and more work to move a bigger, heavier, though powerful guy like Jan Ullrich.
I don't get into velo racing or other non-road cycling events, but I would presume that technology would play a slightly larger role in these types of racing. Much like it does in time trails because of the short distances where the effort provided by the elite riders is nearly identical due to a lack of drop off and very minuscule advantages can mean the difference between winning and losing.
My point of all this is that LA is a genetically superior freak of nature. His body has been tested and measured in countless ways. These tests have shown that his physical capabilities are far superior not just to regular humans, but to well conditioned athletes. It's pretty obvious that he is as close to superhuman as is possible and to discredit him as a product of technology is absurd, ridiculous, and insulting to anyone that knows better.