If you need to be locked up, then so do I,

since I thought of the same idea a while back. Kiosks with large catalogs of the ebooks they have available for purchase and on-the-spot downloads. Plus racks of flash memory card pre-loaded with books nicely packaged in tiny versions of the books' covers. And it would be nice if they sold ebook-reading devices at them too.
These kiosks could be in malls, airports, etc.