Target employee (sorry,
team member 
) here.
If you can't find the iPads in your Target's electronics section, they either have the iPad endcap set up way too far from the Digital Music/iPod section, or they don't have it set it up yet.
I set up ours Saturday night, and it was quite an undertaking given how long a standard endcap should take. The signing even came with a seven page instruction guide on how to properly set it all up and make it look all Apple-y.
Chances are if their salesplan due dates are the same as ours, the iPad endcap and several other endcaps are due to be set by the end of this week. And if the other stores are anything like ours, they haven't quite had the staffing to do so very quickly.
Wasn't there on Sunday to see the grand release, but we sold at least one to an eager guest right when the store opened. It was an older woman who was not very familiar with computers, and I was told that she was quite a handful (for instance, she asked what version of Windows she would need to install on it. Hokay,
here we go...)
I don't think we will have an actual working display of the unit. Even when we got the Kindle, our "display" was a Kindle reworked to display a slideshow of its features and show you what the screen looked like.