I think all you can do is add some common metadata to each of your panorama photos and create your smart album from that. For example, add the keyword “panorama”.

I suppose if you have a lot of panoramas you might not consider this easy. But it really is easy - just time consuming.

Here is what I did and it works pretty well. Some photos with strange cropping may be mixed in at the top, but this will at least help you narrow them down dramatically.

1. Change view to list view
2. Sort by Aspect Ratio
3. Panoramas will be at the top or bottom with weird aspects starting at 100:xxx.

You can also use this to make a smart folder with the following criteria from added rule of Aperture Metadata:

Aspect Ratio - starts with - 100:

Hope that helps!

Found out how to do this in iPhoto so I thought I would share. Simply create a Smart Album with the Criteria:

“Any Text” contains “10800”

Seems to find them as all the Panoramas have 10800 pixels across.