One step further though (or perhaps back, depending how you look at it) how about a rather generic SHA256 ASIC? Put two of them nut-to-butt and there's 90% of your miner; put one into a cryptophone or whatever else uses hashing. This would increase your market by a massive factor, and in doing so decrease your per-unit design cost and thereby price.
Thanks for your advice. Our first generation will be customized for mining only (bitcoin-specific constants baked in, only information about nounces being passed out), but in the future we will make generic SHA256 ASICs if there's indeed much other use.
I guess your "put two of them nut-to-butt and there's 90% of your miner" means two hashing units. Because both "two hashing units in one chip" and "one hashing units, two rounds for a double SHA256" are much more technical viable than separating two hashing units into two chips then using outside circuits to make them communicate.
How small could one make a simple SHA256 chip? If they can fit three complete unrolled engines on a single S6LX150, one can be crammed into a damn tiny bit of silicon real estate.
The technology of our first batch products will not be as good as, say, 45nm. Therefore, we believe they will be small, but not crazily small.