We now know more about Street Fighter x Tekken (SFxT) at Evo 2012.
Mr. Wizard of
SRK has officially announced that SFxT will follow the 2v2 format. This format does not include scramble mode. Gems will also be disabled as they haven't been used in most tournaments due to time constraints.
More details on SFxT at Evo 2012 when they become available.