The smallest Sony laptop
(currently on sale
) is not that small, but neither is the j820.
However they used to have a small one, the U series. The U1, U3 and U101 were small laptops smaller than the MobilePros. However the latest generation U series has a tablet form, with external folded keyboard. It is even smaller tho.
On the other hand, Toshiba has recently released the latest Libretto, which is also very small. I have tried its keyboard, and the keys are even smaller than the Jornada's, and harder to type with. If I ever meet a salesperson friendly enough, I'll ask for a size comparison with my Smartbook, and take some pictures
I guess they're about the same.