I've been chasing an external scan doubler for years. Tried many a supplier. Rare as hens teeth those beasties.
Closest I've gotten to finding a retailer is Softhut saying maybe in 2 months they'll do a new run of their design..
I already use a DCE scandoubler/flicker fixer in my A1200. Cost me A$200, and the picture quality ain't that great, but it's better than squinting into a fading 1084s.
What sort of order numbers would you need for a production run. Count me down for an external model, as long as the price is around the A$250/UKP100/US$150 mark.