Okay, apparently the cinderblock option is counter-indicated in an earthquake zone. (If Metafilter is to be believed: http://ask.metafilter.com/111916/Where-can-I-buy-an-affordable-bookcase).

That thread has a couple of alternate suggestions, though, including the ever-popular "troll Craigslist and be patient" option. Speaking as someone who spends a lot of time on Craigslist, I will say that you can indeed find good shelves in hardwood (i.e. that don't bow). But to find them in a floor-to-ceiling bookcase is always expensive. Have you considered an open-front hutch? It'll be a drawer or two and a cabinet below, and open shelves above. I've seen them as big as 6' wide and 8' tall, but you'll probably want a bit smaller than that.