I think you're looking for a "leather presentation case" or a "leather art portfolio" - although not all art portfolios have rings inside, so you'll have to check. Both of these often come with a handle on the spine and the art portfolio comes in many sizes, from regular binder size to really really large.

They sell them at office supply stores.

Also, they tend to sell them at gift stores, because it's a common graduation or new job type gift - Things Remembered has them. Here's one, though I don't think it has rings inside:

http://www.thingsremembered.com/webapp/wcs/stores/servlet/product_10001_10001_559218_-1_1

Here is a link that might be useful: presentation case

can you get close enough to the Pottery Barn ones to look for a manufacturer's name and product number? Then maybe you could find their actual binders.

The presentation cases or art portfolio often have rigid sides.

I think the presentation cases might be more rigid than I'm looking for, although they are lovely.

I might just ask the PB store if they know where they came from!

Thanks guys,
Lisa