I have deployed 40 1142n Access Points and have them connected to 6509-E switches.
No more than 6 APs per switch and no other PoE devices.
All but 4 have booted and and associated the the controllers. The ones that have not have the folowing in common:
1. Their LEDs cycle through "Red, White, Green"
2. On the switch, the 'show power inline | i gx/x" command gives:
Gix/x auto on 17.3 15.4 Ieee PD 3