I was walking behind the local Wal*Mart near the loading dock and saw this:
That got me thinking about straw bale construction (something I know very little about). One thing I've heard quite a bit is that building with straw bales is only inexpensive in places where straw is cheap. In urban and suburban areas (and very close by rural areas) cardboard is abundant. Could cardboard be a decent replacement material for straw?
The cardboard in the image above is actually baled up. I believe that Wal*Mart is the only place in town that takes in cardboard for recycling, so that might be the reason they formed it into bales. Any large store would have to deal with a lot of cardboard, but I don't know if they would bother separating it from the rest of their trash. I imagine any place like that would be happy to let you take it off of their hands, unless they had to ship it out to receive some sort of credit.
Like I said, I don't know much about straw bale construction and I'm not sure if anyone has used cardboard like that before.
I don' have it at the tip of my fingers, but there have been a number of "baled" architecture projects outside of straw to some good effect. Stone has been baled (in gabion) and this is relatively common now. Carpet and felt carpet padding has been baled and built with, and cardboard and paper as well. If I can dig something up, I will post it here for you and the other readers.
Heck...I should've checked before I posted above...here is what I found in just a few clicks worth of searches...