Yvo of xcores.org has released his preliminary VDP source code for the Xmos XS1 processor.
The specs are pretty impressive:
256×192 resolution ( scan doubled in both X and Y )
2 independantly scrollable backgrounds
32 sprites ranging from 8×8 to 64×64 pixels
Horizontal- and vertical flipping
16 palettes of 16 colors each, for a total of 256 onscreen out of 32768 colors ( 5:5:5 )
Uses only 2 threads ( VGA and Render )