Who designed the AmiJoe in the first place? Couln't he (or she) finish the job? Why dosen't Eyetech help him (or her) complete the board and make the product their own? Seeing so much enthusiasm for this card and other PPC accelerators, and second hand PPC cards always fetching good prices, I think there is a market for such a product.
Owners of classic Amigas will give OS4 a shot if it's bundles with a good PPC card which is readily available at a good price. It's still niche market mind you, but probably profitable, none the less.
Cheerio
Jethro Tull