What really happens in a scandoubler:
See if you can accelerate all signals and then leave black lines in between so you can achieve a fullscreen pic without buffering?
Synchronization of the accelerated sync + rgb signals may be a problem? Or perhaps a load of trimmers for the user to tweak.. :-)
It turns out that he made a second version of the project:
Still no line acceleration, but digital controls to scroll the wide image horizontally. :-)
I'm not sure if that chip of yours will be able to accelerate the actual rgb signals.. the sync is easy enough since it's just 1010101010 at a set pace.. However the colour signals do not pulse at a set pace. :-(