You might consider partnering with a merchant, such as QED or Lee's Razors, to produce the customized Progress for them to sell. One advantage is that you don't have to deal with each individual purchaser and the attention that each purchase involves, such as the the transaction (payment, banking, etc.), individual shipping in and out, emails, etc. It might seem that this approach is more involved in the commercial aspect than you want to get, but it seems that it would be much less time consuming with much less effort. Also, from our end -- the users or purchasers -- the merchant would be in a much better position to sell the customized Progress a lower price than if we bought one and had you modify it.