Just wanted to add: what most of you keep forgetting is, that a generic scan converter/doubler will sample the horizontal scan lines at arbitrary intervals - that's why the output's usually pretty crappy.
For reasonable results, the SD must sample the pixel right where Amy's putting them (at pixel clock intervals); it must be adjustable and/or automatically synchronizing to the pixel stream (like most TFTs do w/ PC like pixel streams) or the resolution must be so extremely high that no pixels are cut in half. If you don't understand what I'm talking about, look at a FF that is tuned way off (little screw): some pixels are doubled, some are missing, some even flickering - not a pretty sight.
That said, I don't believe there are many (if any at all) non-Amiga scan doublers around that are of any use.
