Scan Doublers

[humppa]

You might also want to have a look at the DVDO Iscan Pro/Ultra Series. Functionality is quite similar. Please note that the refresh-rate they output might be too low for most TFTs (especially if it's a 50hz-PAL signal). These devices are also quite expensive compared to "real" Amiga-scandoublers.

My idea is at the moment to buy a cheaper VGA box such as the "Grand Video Console II" and use the S-video inputs (instead of Component) for a gain in image quality. Genlocks are cheap nowadays and some of them can convert the RGB signal to S-Video. Has anybody tried this yet?

Another advantage of this solution would be that I could hook up my C64 to the Composite port so that I can toggle between Amiga-PC-C64 signals (all on one monitor).

[humppa]

As soon as it accepts RGB over the Component cable, the cabling should not be too difficult. There are VGA->Component cables offered on Ebay quite frequently. You would just need a 23p->15p VGA connector.
In most of the cases, however, things are not so easy with a Component input since it is used for YCbCr-signals rather than RGB-signals. So a signal-conversion would be necessary (not for the 1404!).