I've relaunched another site that I originally deployed using MD-Pro (a PostNuke fork) and osCommerce. I used an interim build of MODx (somewhere between Tech Preview 1 and the next release) to build this, so it had the latest TinyMCE and FCKeditor versions in it, and the client likes the system much better than the complexity of the MD-Pro / osCommerce solution we had previously. We're currently just using Buy Now buttons from PayPal for online purchasing, but I'm going to be building a PayPal shopping cart enabled system for them soon.
They're still preping content for the site, so it's not complete by any means, but a great testament of how easy it is to go from the Nuke and osCommerce worlds to MODx.
http://dornersjewelry.com