Unless you can produce money from thin air, there really is no other option to have customers pre-pay some orders.
Later batches might be available with less pre-payment required.
The only reason they have trouble financing is because of insanely high risk. Most businesses don't have this issue. Other btc miner mfgs didn't have this issue.
The other option is to not produce. I have never purchased a product that has not yet been developed, the concept is to risky, but that is my opinion, I am sure a lot of people have taken bigger investment risks than I and made loads of money. I am more of a safe and steady kind of guy.
Later batches with pay and ship promptly will probably be very successful if they are priced appropriate to market value.