Technically you guys are forgetting about Radical Dreamers (Japan-only semi-sequel to CT), but yes, both it and Chrono Chross were semi-sequel/future installments. It's like doing Mega Man X, and now coming back to do another Mega Man title.
I would be one happy Moogle if this panned out, though. A direct CT sequel? And something interesting on GBA to link up with it? And it would now be best possible, due to the Square Enix merge.
Sadly, that would be a "gamer dream" rumor, and lately, being a Nintendo fan and hoping for those kinds of rumors to be true are too often HUGE letdowns. Konami's going to announce this, Capcom's going to show off that, heck, Megat- well, do I have to finish that word? ;P Next thing we know, Mario Kart will be strictly offline.
So file me in the "I wish it was true, but I'm not likely to hold my breath" category. Still, the timing would be right...