Ten years ago (at least), back in the 90's, I was at a coffee shop and saw someone typing away on a foldable, full-sized keyboard connected to a Palm device. I remember being impressed that two highly pocketable devices could provide such an efficient, impromptu work station. Pocket PC's have had the same capability for years.
Now that I have an iPod Touch and some use for this setup it's disappointing that it's not possible and doubly frustrating because the hardware capability is there.