Finally I had some time to finish my new plotter.
To build it I have used parts from one old scanner (x and y belt drive) and head holder from old printer. To up and down a pen one servo is used.
The "brain" is of course an Arduino and motor shield.
I also have written a software to control it. The software imports HPGL (plt) files, generates preview and controls the plotter.
Everything can be powered from usb but for higher speeds I use external power supply.
I will release source code when it works as I want.