Well, if someone wanted a quick % out of a half million dollar investment, maybe this could happen.
In the normal financial circles this would work as follows:
1) group buy collects the funds in a bank A's account
2) bank A issues a letter of credit
3) bitcrane takes the letter of credit an obtains a loan against it from bank B
4) using loaned funds bitcrane manufactures the miners and ships the miners
5) upon proof of shipment bank A releases the credited funds to bitcrane
6) bitcrane repays the loan to bank B
In other words:
a) bank A is supervising the availability of the funds
b) bank B is supervising the timeliness of manufacturing and shipment
But this is Bitcoin, there's nothing normal about it. In particular many Bitcoiners are actively against banks and conventional finance.
This free market is exactly what you people were screaming for all the time. This is exactly what you wanted. You made the soup, now eat it.