Knoll, has KnollFSL, cad data of all of their classic, (Knoll is the manifacturer/reseller for Mies, Corbusier and other classic stuff) it is usually on disc, but you can download it from their site.
And it is free, just register and download.
One problem with some library out there, not to name it, is proportions. Mabee it is more user friendly for a max user, but it is not really accurate. ( My boss has an eagle eye for this kind of details)