Will people still be able to pick up the iPad and handle it?
Maybe have a back protector on it, the kind that uses water when it's applied. When I removed mine, it took me about 5min and a lot of stretching and pulling. On the back protector, use some form of mounted loop or hook, basically anything that your cable or even a laptop lock will be connected to.
The back protector serves a few uses, protect the iPad from scratching, gives the user a little more grip, attach your security device and of course anyone attempting to remove won't be able to do so quickly. Of course this is under the assumption somebody is watching it as well.
Not sure if it's the best way, but it's one way to do it.