Papilio is an open-source FPGA project intended for education, hobbyists, engineers, or anyone interested in learning Digital Electronics in a friendly community. It offers FPGA development boards and add-on application modules called “Wings”, that makes a easy to learn platform for beginners, and powerful design and prototyping tool for engineers. Read more here: Papilio.cc
There is also an Arduino Core for the board that is based on an AVR Softcore processor and comes bundled with a modified Arduino IDE: Arduino Core
To teach my table some brightness levels I would need a fast hardware to do the shifting faster and the papilio seems to be the right hardware for the job. Porting the code and writing the driver core is in progress…
The current driver core has some minor issues (see the green dot in the center of the left edge on the second image) but supports 4 bit brightness level control with brightness linearization (internal 7 bit brightness to 4 bit corrected).