Concrete Walls?

Something I really hadn't considered too much as an option was a solid concrete wall. I'd always figured concrete would be prohibitively expensive, but that prejudice was probably instigated by looking at how much a bag of pre-mixed concrete costs at the local big-box hardware store. I made a couple of posts over at Ownerbuilderbook.com just as feelers for the cost and merits of various materials (CMU, ICF, SIP, etc...) for an owner-builder. One of the posts recently got a reply and referenced that many CMU walls would likely require reinforcing by filling some of the hollow cores with concrete and re-bar. This was something I knew, as it is likely a requirement by many building codes especially if you live in a hurricane or earthquake area. The post made a quick reference to something I didn't know though, which was that the cost wasn't as high as I thought for reinforced concrete. A quick internet search brought up a site for a software designed for building cost estimation called Goldenseal. I'm not really interested in the software, but the estimates it gives for a solid concrete wall vary between $6-$9 an hour per linear square foot of wall, the upper end being for a twelve inch thick wall. Sounds expensive, but here's the real savings: This includes the cost of formwork! Assembly and disassembly of all wooden forms needed to pour the wall. If that is correct, a poured concrete wall is a considerable time savings over a DIY CMU wall, especially if you can get it at the cheaper price. This needs more research...

As a side note, I just found Perma-Form ICF block offering a $6.99 form block which puts their cost per square foot of wall at $1.99 per square foot of material. Wow, look for one thing, find another; questions begetting more questions!