From the Cisco Learning Network:
In alignment with CCIE level requirements, Cisco is adding L2 switching features to the CCIE R&S Troubleshooting exam through L2 IOS software on Unix (L2IOU) virtual environment. The new feature will be available starting January 17, 2011.
The CCIE R&S exam consists of 2 sections – the troubleshooting (TS) section which runs two hours, and the Configuration (Config) section which is six hours. The Config lab utilizes actual physical devices in racks, whereas, the TS lab uses a virtual environment under IOU. IOU offers a very realistic simulation of router (L3+) features in the TS lab but until now had no L2 switch capability. With the addition of the new L2IOU, the TS lab will now include both L2 and L3 capabilities in the virtual environment.
Thanks to ziyadb for pointing that out.
UPDATE: I fixed their incorrect date. =)