Me and my friend collect the retro laptops so we have quite a few. Here are the mini-notebooks we own so far, all of them are smaller than todays smallest netbooks, and just a bit bigger than a DS.
Libretto 70CT (Mine, apparently the smallest computer ever running a full version of Windows.):
Palmax PD-1000 (My friends, it's extremely rare, there's not much info on it unfortunately. A unique factor about it is that it has a touch-screen.):
Sony VAIO PictureBook (It has a built in swiveling web cam, also with the Sony Webcam Studio program for special effects):