Well its landed and for flex connect read H-REAP on steroids, at least thats my take.
The 5508 controller can manage, with the latest code, upto 100 H-REAP groups with 25 access points per group. This new platform can deal with 500 sites and 50 upto 50 access points per group, 2000 access points and 20000 clients.
Licensing should be software upgradeable starting at 300 access points.
There is more information here