So the PS Vita TV is out in Japan. And I've already seen several posts saying, "OMG Vita TV is region locked!!!" So I did a little digging (since I don't actually have the device) and people are saying this because they can't log in with their US/EU PSN accounts. But it seems to be more an issue that the US/EU PSN servers don't know anything about the Vita TV yet so it gives an error, rather than being an actual region lock. This would presumably change when the device is released in these regions.
Still, I would probably hold back on importing for now. In addition to the PSN issues, US/EU games that need to be patched for the Vita TV (because of the lack of touch controls) presumably aren't being patched yet when the system isn't even out here. So there isn't much you can do with the device other than playing Japanese games. For now, anyway.