Because I monitor mame WIP thread I saw some news about Quantel Paintbox emulation in MAME (0) and then I randomly followed some links to other Quantel systems
Like HAL (basically like hardware compositor)
99 layers of SD images or video, up to 15 min storage on 20 disk array!
if you have half of hour you can watch this demo from 1997. Biggest thing so far for me? We are free to use old-fashioned optical effects in front of real camera too :)