Jim ~
Great review ! You don't know how many times I had that B-400 in my hands at the LHS in the past month...Lol.. It was one of them head scratchers for me. I would pace the LHS debating. Every craft has it's flaws, so I wouldn't expect perfection from it, and some day I just might get one. I know the power to weight ratio is excellent on them...
I'am not sure on the AVI format for You-Tube... I'am just using a cheapo $280.00 digital camera from Wal-Mart that shoots my videos, and then I use Kodak Easyshare software (Free download) and it takes the pictures and movies from my cam to my computer, and then to You-Tube.

I think the limit is 1000mb, not totally sure though. The AVI format I would think they would accept, but what do I know...

I'll have to scope it out next time I'am downloading there in case you don't find a solution.
I would love to see a video of your B-400 though !
Take care guy,
~ Jeff