Dan:
I understand your concerns, and even though I still don't think heat will be an issue because the regulator will be off 95% of the time, (I can't control what people hook to the board and even a 5A reg will get hot if they short it, but it's not an Arduino so most shouldn't be connecting anything too crazy) I'll take another look and see what I can find as far as a 3v3 regulator goes. I'm not against less heat and more power.
As far as size goes, the board's already at the absolute maximum. It has to fit inside small props, and I've done a lot of research to determine exactly how wide and tall it can be and still fit inside most, and it really can't be any larger than it is now. So at this point, my goal is simply to maximize the power output at that size, without driving the cost up too much.
And as far as prototypes go, while I don't plan to have 1000 of these made, (I wish! ) with the first batch likely being around 50-100 boards, I will of course have a prototype assembled first to make sure everything is in order. Doing my best to ensure that the board works the first time though; that's why I'm asking questions to verify if my assumptions are correct or not. 