Yeah, I've also wondered why Andy is not making/selling an off-the-shelf vga to scart cable. The signal levels are ok on both sides, so there's no amplification required...
In fact this is the easiest and cheapest way to get a good "arcade monitor" in Europe.
I THINK that cable you indicate would be ok. Gernerely you've got red, green, blue and the syncing wires to think about. There's plenty of info about the connections on both sides on the internet. As long as R,G,B and comp.sync end up at the right pins, you're fine !