New Architect Magazine has an article that they call “Making Mistakes Well” on offering contingency plans to increase revenue:
LandsEnd.com decided it could do more than just display the typical “out of stock” message for unavailable items. Instead, the site now presents an inventory alert feature that tells shoppers when an item will be available, offers to send email notification when the item arrives, and shows shoppers similar items that are available immediately. The conversion rate at LandsEnd.com is 11 percent, one of the highest among online apparel retailers. Site creators say that this sort of dedication to the customer is a major reason why.
37 Signals also has a white paper on contingency design.