They used to make a 12" PowerBook that is still regarded as one of the best form factors Apple ever made. I doubt they'll start that again, though, or trend any smaller because as the article mentions, Apple already has too many competing products. In addition to the Macbooks the article lists, I think the other end of the spectrum is the iPod/iPhone. These are essentially tiny netbooks; able to do most of what I would want a netbook for in an even smaller form factor. So I too strongly doubt that Apple will release a netbook.