very interesting.
I already posted a question

I had a similar idea but I haven't enough TV repair knowledge to realize if.
THeoretically my idea has sense but i dunno how to realize it.
a normal raster TV has 2 ramps generator in order to draw a picture on H and V. These 2 ramps have different frequencies of course.
My idea is to substitute these ramps generators with the X and Y signals removing all the parts about blanking signals and so on.
blanking has to be adapted in order to be controlled by Z signal.
In this way you don't need any additional board with amplifiers on but only some low power signal adapters.