On that note, one thing I've wanted to do for quite some time is an application that would allow you to open an image file or a set of image files with a particular style of map and it would try to replicate that style with OSM data. Ideally emitting that style in a Mapserver mapfile, or a Mapnik style file, or whatever. If you prefer German-style road atlases, you should be able to have them with OSM data. Doing such things by hand seems incredibly tedious, though.