On the 21st December “Mr. Spiv” updated his page with following:

I put two technical demos online showing how HBLANK emulation can be used… effects are lame and done in hurry.. but I’m a lazy man.

The description:
hblank.fxe is a simple example of HBLANK interrupt and DMA triggering emulation. The picture has 256 colors and the color bars on background are done changing the background color (LUT color 0) on every raster line. Less than 4KB of data needs to be moved per frame refresh in order to make all these effects.. so very CPU & BUS friendly. Demos run at 66MHz and almost 60fps…
hblank2.fxe does basically the same but with 16bits picture and two layers.

Thanks to Mr. Spiv himself for the news.