In the real world, a million units is way larger than the actual market size, and ten thousand is more realistic (maybe still too large). Seeing how producing a relatively large quantity of units is not an option, those machines are going to turn out to be pretty expensive
Makes you wish you were stinkin' rich 
It should be possible to come up with a reasonable estimate 
Then by all means, be my guest. Start your research and give all of us a reasonable estimate. But I think the term "reasonable" is too subjective and any estimate will be just a ridiculous figure that won't be anywhere close to reality.
Your wealth would be better served by investing in a Replay board or a Minimig......or better yet, if you're so enamored with classic Amigas, just go out and buy some. They're still pretty cheap on eBay and other places.