Ok, after a while searching for a good, portable notebook (read: ultrathin/ultrabook), I think there is not one that I would really call "good", except /maybe/ the Toshiba z930.
Therefore, I tried making my old Acer 1810tz (see link) a little more bearable by replacing the hard disk with an SSD. The device used to be awfully slow.
With the SSD and after replacing the operating system with a new Arch Linux installation,
it feels blazingly fast, is very nice to work with except for the screen, which in my opinion really, really sucks. Otherwise, it is quite ok for me until some manufacturer comes up with a decent notebook.
The bootup time is about 17 seconds, and it shuts down in about 2 (!) seconds.