Hard to say, DQX was the first DQ to be developed internally. That was probably a spacial case though.
Assuming Horii does reach his deadline / release date of 2016.
How long do we anticipate the game has been in development.
Let's say they started in 2011 or 2012 which means a 4 or 5 year dev cycle.
Would Level 5's project of Wonder Flick conflict with the development of DQ11, even if it's not Level-5 then what other Japanese studio would Armor Project outsource to?
ArtePiazza handled the DS and 3DS versions of the Dragon Quest remakes. so are we confident they will handle a DQ title on either the PS3, Wii-U, or PS4?
Another developer to consider who has been rather quiet and hasn't worked on any console projects for some time is tri-Ace.
It's up in the air who is handling DQ's development. Outside of one game in the entire series (DQX), every single game was outsourced and wasn't handled internally at Square-Enix.
It was always Armor Project plus the outsourcing company (Chunsoft, Heartbeat, ArtePiazza, Level-5) that handled development.
So it depends on who Horii decides to have a working relationship with. With SE on full charge getting FF15 finished and KHIII just starting development under Nomura, I'd say it's likely that DQ is being handled by an outsource company as usual.