Today is the next step in evolving Commerce Server. As of this morning, the Commerce Server 2009 Template Pack for SharePoint 2010 has released and can be downloaded at http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=cfd0c459-5a11-4de6-9085-52d59e8d38e6.
What this release provides is an updated version of the existing Contemporary Site for both Web and Mobile devices that runs on SharePoint 2010, along with the requisite source code for customization. It also updates the Profile system to support the new claims-based authentication mechanism in SharePoint 2010.
I would highly encourage anyone starting a new deployment to start here. For those with existing sites, the Profile update (and associated site code, to be used as a reference) are absolute must-haves to get an existing Commerce Server 2009/SharePoint 2007 site to run on SharePoint 2010 (there is no way to actually get it to work without these fixes).
Hope this helps!