Everyone knows Pandaxpress doesn't deliver. Pandamail is useless, all letters are scratched on trees with bamboo, illegible nonsense about giggles and rainbows or cute and cuddly, nothing relevant to any battle topic... Stupid Pandas
Really? Never knew that. Maybe they'll add one to panda land in the next patch. Maybe not. Who knows?
Probably not, considering the reason there is no mailbox is to keep the neutral race from being the middle man for trading between horde and alliance characters.
They could always just make it so you can only send heirlooms until they pick a faction.
Pre-faction-choosing Pandaren are considered their own separate faction anyway. In fact, for a little while on beta, it DID work like that way. I'm honestly surprised they didn't put a box in for live.