Recent rumours have claimed that Xbox 720 currently goes under the working title Durango at Microsoft, and this seems to have been verified by a tweet from Crytek's Sean Tracy.
Claiming he was enjoying a Durango summit in London, Tracy quickly recalled his tweet, but not before gaming sites all over the world have picked up on his apparent indiscretion.
While this is no definite proof that the machine is codenamed Durango or that it will be shown at E3 in June, it's certainly adds fuel to the fire.