Your 8 greyscale dither could use some hblur effect
Since we're talking about imagine conversions and dither, here's my hblur one
[simulated image of what it should looks like on the real system or emulator that doesn't drop frames]
[what it looks like prep'd and going into the pce code]
[hsync frame 0]
[hsync frame 1]
It's a 30hz pic. Instead of switching between two different dithered pics in vram, this is just a single pic. The upside is vram savings, the down side is that the color depth for RGB is only increased to 12bit(4bit element) from that of 9bit (3bit element) RGB. The original image needs to be patterned dithered into vertical lines instead of XOR pattern. That way each frame *IS* XOR pattern from the hsync shift on every other line.
http://www.pcedev.net/hblur/example_robo.pce Warning: emulators will drop frames now and again, spoiling the effect a little. (I haven't tested this exact revision on the real console, but the previous revision worked fine - so this should as well.)
