You can say that the item was lost or broken and refund the purchase price.  eBay wouldn't care because they still get paid.  How would anyone know?  Normally nobody would, but it was really obvious in the case of item 290041837749 where more than a dozen ViewSonic LCD monitors was offered in a dutch auction by Hypermicrosystems  ( http://myworld.ebay.com/hypermicrosystems/ ).  The winning bid price was unexpectedly low so Hypermicrosystems just refunded payments to the bidders.  You might buy the concept of one or maybe even two of the items being broken or lost, but not the whole lot.  Bidders are allowed to send messages to each other so just be careful about being too obvious when cancelling a sale.