Regarding the CHA47 being a hack, morsel covered the "A47" part of it, but I was also referring to the fact that a CHA47 uses a Hansen board in a way it wasn't intended to be used. I've built a few CHA47s, and while it's preferrable to building A47s on protoboard, the CHA47 is still more difficult to build than a circuit board designed for that amp would be. I can build a META42 in about the same time as a CHA47, and the META42 has something like twice the number of parts.
I know this is gonna sound biased, but now that the META42 is here, I think the role for the CHA47 is greatly diminished. That isn't to say that the Hansen board is useless -- it's still great for its intended purpose, as a CMoy+crossfeed. And, a CHA47 is still smaller than a META42.
On the issue of price, it isn't very productive to talk about prices of DIY amps in the abstract -- I think I'm speaking for all the DBSE'ers here, not just myself. I can build a basic META42 that costs less than $100 that will sound and look good, and I can make a killer META42 that costs over $400 without straying from the path of reason. What does a META42 cost? The question's too broad to answer.