Just to confirm what others have said - 5 day max ticket.
The more interesting question that I feel is important to ask is why. Why do they stop limiting tickets at 5 days? It was said it was to keep the "local/seasonal" crowd from purchasing a few extended stay tickets in lieu of the ever increasing annual pass rates. If that is true, then why again do they want to turn business away? They could easily make extended tickets available only through DLR hotels or Good Neighbor ones and link them directly to the dates you have a reservation.
The parks have more than enough capacity in terms of rides an attractions for higher attendance, so what gives?
I suspected (and had someone pseudo-confirm on my last visit) that get this - even though they could cram more people into the resort and the parks (especially DCA), they've already determined that they are comfortably in the zone where guest satisfaction is high and they don't want to adversely impact it by not being able to handle the crowds.
So, in essence, they are turning business away.
That is why they participate in the So-Cal Pass that includes tickets to other attractions in the area. "Take your business elsewhere", "Move along", "We're not the droids you're looking for".
Could you imagine WDW participating in an Orlando Pass? If you think that could happen, I have some PowerBall tickets and a bridge to sell you.