Look had these sweet new ZED carbon cranksets that are fully carbon all the way from tip to tip, and are one piece!  They come as standard on the new 596 TT bike (posted below).  Given the molds are expensive, these cranksets manage to fit everything into one model, read “more” to see how these adjust from 170 to 175 and more!
First bit of adjustability: The two bolt patterns on the spider allow you to run regular or compact cranksets.
To install, you slide the non-drive side crank through the BB hole, then tighten a cup over the threads on the silver race.  The entire assembly weighs only 325g (without rings), and just 475g with Look’s rings (shown below with DuraAce).  That’s a considerable savings over a traditional crankset/bb combo.  And they use a BB50 (50mm) set up, so they’re stiff.
Second bit of adjustability: The Trilobe technology gives you a rotateable insert to install you pedals on, letting you choose between 170, 172.5 or 175mm crank length.  Pretty ingenious!  Shown above empty and below with a pedal and the schematic.
