Well this came out of nowhere! Nothing (probably) to do with E3 celebrations, Square-Enix have announced a multiplayer action RPG for the 3DS called "Final Fantasy Explorers" via the Japanese Jump magazine. It's also being developed by Square themselves, but has no projected release date yet.
Here's the only scan so far;
It seems like Square are trying to take a bite out of the Monster Hunter pie with this one, with potentially a little inspiration from the probably-dead Crystal Chronicles mini-series.
So far there doesn't seem to be much info, but here's what I've gathered from the few sites to have reported it so far:
The plot revolves around gathering crystals.. didn't see that one coming
There is a classic Final Fantasy job system, the jobs shown so far are White Mage, Black Mage, Monk, and Knight. There will be many more.
You hunt summon monsters like Ifrit who is pictured in the scan
again, it's multiplayer-focused, hopefully it'll be online!
Up to 4 players.
Many weapons to choose from
[source]
Official Website (Japanese)
PS. this is literally the first Topic I've made on SSMB since before the site crash all those years ago, so I probably made a boo boo in the OP somewhere.