Capcom's Corporate Officer/VP of Strategic Planning & Business Development, "Sven", recently commented on a a fan's concerns for a third entry in the ZX series.The "official" status of ZX3:
"To be determined..."
I figured as much, however it's reassuring that Capcom is looking into the issue. My guess is that Capcom is waiting to see how well the "National" version of "ZX Gigamix" fairs in August. (National version is being sold in stores nation wide across Japan, previously Gigamix was an online only purchase)
If Gigamix is succesful, that could be a sign that interest in the series still exists, thus increasing our chances of seeing a third ZX title. So pretty much, the fate of ZX3 is riding of fan support.
We'll just have to see what happens. After all, IntiCreates has their hands tied with Rockman 9, so development of ZX3 will likely happen (if it ever does happen) after RM9's release.