DrawBot
thingiverse
Still a work in progress (untested). Requires two micro servos (about 4.5 g), but you can redesign it to fit other servos if you like. You can easily turn it into a TRS robot if you want, or just control the servos with a microcontroller. (http://makezine.com/projects/trs-drawbot-2/)
Download Model from thingiverse
With this file you will be able to print DrawBot with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on DrawBot.