www.gog.com is a site for... good old games. Games that are cheap, downloadable, and work on XP/Vista. Later 7 I presume. Now I'm not sure how this thing works, who are the people who make the games work (using dosbox), and is there anything in the process that requires much from the original Developers of the games. And how are the sales distributed. But I do know that if Battlespire and Redguard could be purchased from there, they would sell. I'd be first to grab them.
Bethesda, if you can do anything about it, make it happen.