After watching my 8 month old nephew beat on the iPad playing Baby Piano HD, I would have to disagree on the damage part.

My son have jumped on it stood on it and stamped on it. Not a single scratch or loss of performance. It is a pretty sturdy piece of hardware

As is the rest of the Mac line- my 3 year old literally ran across my MacBook pro and no damage was sustained.

I can feel you on the stealing aspect (though with the optional free engraving you can really limit the resell value), but they are not easier to damage than desktops. There are no moving parts. Unless you drop it in a sink, you're going to be OK (that would be ill advised with a regular PC too). The software is also incredibly hard to screw up, which lowers IT support costs.

An iPad would also be a lot easier to lock away in a secure location, though.