The pack­ag­ing for a Revenge of the Fallen Mis­sile Mania game fea­tures a redesigned Mega­tron on its front cover, despite sup­pos­edly not being in the movie:

For more clues on Megatron’s return we need only turn to the back of the toy boxes:

Starscream:

The moment his sen­sor net reg­is­tered Mega­tron going offline, Starscream knew that bat­tle was over and the Allspark lost. He con­verted to vehi­cle mode and boosted for outer space, hop­ing to buy enough time to rally the Decep­ti­con sur­vivors. Return­ing from Cybertron bear­ing the marks won dur­ing his reign over the Decep­ti­con army, he is cocused on con­quest. With a new army behind him, he has the strength to pur­sue his own goals, and per­haps, when the time is right, bring Mega­tron back.

Not to men­tion the Mega­tron Tank mode…