Clearly, shaving off every gram of unnecessary weight is a priority in the laptop/netbook market. For rMBPs, a major (though often neglected) area of extra weight is the power adapter--essentially a brick the size of a fist. Finsix had attempted to design a slim power adapter (the Finsix Dart) but as their designs slowly materialized, they abandoned including compatibility with the 15" rMBP. Contradictory rumors claimed they were talking with apple or that apple was unhappy with their design. USB-C opens up a new avenue in charging laptops. Perhaps a power adapter using USB-C could be much smaller? (Something similar to the iphone charging cable?) Perhaps we will soon be able to charge rMBPs through USB-C ports? Perhaps these new ultra-slim adapters will be shipped with the first new MacBooks (just as a "slim" adapter was shipped with the airs) and then they will be incorporated into the rMBPs as they adopt USB-C?