For all the people with large number of chips, the most feasible option would be a double density board with 20 Chips at about 100eur.
Even larger boards would pose problems that I don't want to face, doing such a time-constrained project.
I don't want to burden you burnin since i know you have a lot of work to do, but please have in mind posting some pros and cons with the double density boards.(not now, but when you are ready to take orders)
I will try to help...
Pros-
-Lower cost per chip
-Higher chip density/less space
-Greater hashrate per board, of course
-Greater MAX mining power (if you only have 2 USB connections, you can only plug in 2 machines, and if they both have 2x chips you have 2x overall mining power)
-Less board to make overall, less work, less time, less resources etc
Cons-
-Heat may become a problem
-Designing 2 boards as opposed to one
I really think the pros outweigh the cons to a very large extent. Really, for burnin, the biggest factors are going to be the initial time of designing a larger board, vs the time saved later making fewer boards, and then the economics, of selling x boards at 80EUR apiece, and making 80x EUR, or selling (x-2y) boards at 80 apiece and y boards at 100 eur apiece and making [80(x-y)+100y]EUR which will range from 50x if everyone opts for the 2x boards up to to the original 80x. In my opinion, I would much rather invest half as much time and get paid 1.25 as much money (per hour, based on 50x/.5(80x))