Alex's points about the possibility to run various retro systems is a good one. IT's just too early for that level of development as there are maybee what... 10 minimgs in existance? Moving along to get 10 units made and sold here on Amiga.org to get some level or tinkering done on the thing.
As to the low cost of Amiga keyboards, game controllers, etc. I've had a hard time as most parts show up on ebay and are pretty expensive esp. when buyng from UK. If I was in the UK I'd be in a better place as it seems there was a mass appeal for the Amiga.
On any weekend here in the us you can pickup PC mouse, keyboard, memory card for $3 usd. I can't do that with AMiga parts.
For the American Amiga user Scart (one of the great benefits of being a European Amigan) does not apply so we rely on scan doublers, 15.75 khz monitors, and 1084 monitors FOR RGB.
Also the fellow selling the CO-CO Amiga scan doubler does not have any AMiga units for sale. He's currently working out some issues with an Amiga version right now.