No idea when Pretendo Network will support it but it supports Monster Hunter 4 Ultimate and Generations. I think if you want to play MH3U multiplayer you need to emulate it on something and use the LAN connection feature of the emulator.

On the note of emulation you can move your MH3U saves between devives using checkpoint and FTPD. So not all hope is lost.

no definitive date yet unfortunately :/

i know at min uts being wirked kn last update i know was last week working severs out