CoolApple Thunderbolt to Gigabit Ethernet Adapter
Use the Apple Thunderbolt to Gigabit Ethernet Adapter to easily connect to a high-performance Gigabit Ethernet network. Small and compact, it connects to the Thunderbolt port on your Mac and provides an RJ-45 port that supports 10/100/1000BASE-T networks.
P.S. Didn't see it mentioned in the keynote, so sorry if it was
EDIT - http://store.apple.com/us/searchres...=/us/product/MD463ZM/A&t=thunderbolt+ethernet