Unlike music CDs, you can't just drag-&-drop any file onto the disc and have it play in a DVD player.

That depends on the DVD player. The ones that are advertised as being able to play DivX files will generally play most anything. My brother got a cheap one at Wal-Mart (like this one) that plays most anything such as WMV, MPG, and DivX or XviD AVI's. It has a built in file browser so all you do is drop the files on a DVD or CD in ordinary "data disc" format. Of course, it also plays proper DVD's as well.