After the previous debacle with the english to spanish translation of "No Va" I seriously doubt GM will ever make that mistake again.
While GM has cancelled "Zeta", they have not cancelled RWD cars in favor of SUVs and trucks. (Bob Lutz confirmed this himself on his web blog.)
Also, a well known GM insider and F-body enthusiast has said on several messageboards at several times that a new Camaro would not be "retro".
No idea of when, but Camaro will return... someday.