I have the same problem when I do reset all data on my jailbreak iPad. I did restore from iTunes. Before connect to iTunes you need to enter into Hard mode by press and hold power and central button. The screen will display apple logo and disappear again. Context your iPad to iTunes and the iTunes will ask for restore.
Like Gentlefurry said sometimes your iPad will hand on the apple logo for a long time. You cannot restart. But when you connect to iTunes later, it will restart.
My iPad will stuck every time I turn off and restart. I need to connect to iTunes to restart it. I think I have delete it's booting files maybe. Has anyone here has the same problem with Jailbreak iPad (I jailbreak through Jailbreakme.com mine version 3.2.1)