Is there a way to install Lion but leave initial setup options?

Once you've completed the install, shut down and don't turn it back on. When the new user gets it, they'll be greeted by the intro video and all that jazz.

 

I imagine you can just force shutdown by holding the power button.

 

What the above poster said, on restart, press and hold the power button and force a shut down, this shouldn't affect your computer.

 

There is a setupdone plist file that can be deleted (at least in Snow Leopard), this way you can still test everything and run updates.