Cactus Commerce, a Gold-Certified Microsoft partner, recently announced a new offering entitled CommerceLive.  Commerce Live is unique in that it sits firmly in the middle between the ASP-model eCommerce offering and the traditional on-premise offering.  This gives retailers and consumer products companies the flexibility of an on-premise solution (the customer can bring the site and its assets in-house), the pricing options of and on-demand offering (more options beyond standard software licensing + implementation) and the out-of-the-box capabilities of a on-demand solution.     

This solution is built on the Commerce Server 2009 and Microsoft Office SharePoint Server (MOSS) foundation.

More information on the new solution:

http://www.microsoft.com/commerceserver/en/us/Partner-Showcase.aspx

http://www.cactuscommerce.com/commercelive/Pages/rolefeatures.aspx