Australia! I didn't see that coming.
Tell me again, what is the motivation for a metal box? When someone says "tig welds aluminum" that can be loosely translated as "costs a lot of money". I am under the impression that we are trying to ensure voltage isolation from the rest of the car's systems. Last thing we need is a bus bar to accidentally touch a metal box...
For the 15 boards in the next round of testing, DEFINATELY shop around. You should be able to get much better turn-around times, if not prices, through other board houses.
Thanks for taking on the cost burden to keep this thing rolling