Monster Hunter 4 releasing September 14 in Japan, two special 3DS XL's also announced (Up: New trailer)

[Nem]

It has online play so its pretty much garanteed to release in the west. If it was Japan only it wouldnt need that feature.
I ended up passing on MH3U, but i hope i will get MH4. Hopefully they speed the combat up a bit and reduce the envyronment mats grinding.