This just occurred to me today and it would be really nice. I've bought a few apps I no longer want/need and would be willing to sell them to someone else at a discount to recoup some of my loss. Any thoughts on this? I think it would need to be an update to the android market to have an option to 'transfer' to another user so updates for the app would show up in the market. You could keep the developers happy by giving them an option to make their apps eligible for this or not. I suppose this would only be feasible for apps that are also the type that are private and can't be backed up to the SD card with something like Astro File Manager.