I hope this is the "New PS Vita" I've been wanting Sony to make. Given Vita pretty much only exists to serve the Japanese market and Asia, and it'll be getting more PS4 ports than anything else (compared with PS3 cross platform games), Sony should definitely make a Vita that's forwards compatible with existing games but will run PS4 ports a bit more smoothly.
I'm not buying it, though, I just can't see publishers wanting to support a second TRINITY mode like they are forced to a NEO mode. Sony doesn't have that power over developers with Vita like they do PS4. And Sony arguably would be better off trying to make the PS4 a success in Japan rather than stick with a platform that's basically a dead-end. I can see NEO and PS VR being a "relaunch" of sorts for the format in Japan.
It's more likely that the event will focus on Neo, and Morpheus (PS VR), which launches the following month. If we do get a "New PS Vita" it's more likely to debut at TGS.