Won't scale to 72GH/s for 340 USD... more like 10.000 USD, which is in line with what Avalon is charging.
BFL might be trying to get economies of scale as they (possibly) realized they shot themselves in the foot with pricing. Then again, their ASIC is on a smaller process so each unit might be cheaper than the Avalon ones (so many variables...).
The Avalon 66GH/s has been measured at 620watts by at least one owner, and uses 240 chips that run at 275MH/s not 300MH/s even at 300MH/s we would be talking over 40watts per 16chip Klondike board. Personally I would wait until the chips have arrived, been fitted to a board and measured running before making efficiency and cost claims. You might suddenly find the 16 chip board needs more cooling or who know what other issues.
I'm not sure what you're saying. Even if BKKcoins needs to add 10 or 20 or 30 USD in the BOM, say for cooling, then end price for a 240 chips machine will be around (lazy math coming) 15*400 USD = 6000 USD, without shipping and PSU. That's bang on with the 75BTC (8475 USD) that Avalon is asking, at the current BTC/USD value (around 113 as of this post), assuming Avalon wants to make a profit, 30%-40% seems like a reasonable markup (6000*1.30= 7800 USD, 6000*1.40 = 8400 USD).
BFL OTOH is so much cheaper it's scary. Maybe they figured they could release their ASICs at those prices and totally underestimated the demand. Now they realize you actually need a whole infrastructure behind their production, probably need to hire more ppl and have generally increasing costs (not to mention their engineering blunders). Ramping up fast is messy. and costly.
I think BKKcoins is in the right numbers, ballpark with Avalon. BFL is so much cheaper it is actually worrying.