Try looking on Craiglist, the local paper, the yellow pages or
online for local guys with custom sawmills. (Woodmizers). They produce fine sawdust and in surprising large amounts. With thin kerf bandsaw blades 1/16-1/8th inch, it makes for some really nice nice sawdust for cordwood construction, sawcrete, pycrete and other applications.
We can buy it buy the cord here from the local sawmill, however it is getting expensive due to their own consumption in their boilers to make power for their mill, and because the pellet companies buy it to make wood pellets for that new industry.
As you found out, wood from the utility companies is not all that great. It is easy to get, but I have noticed a lot of people on here trying to use it for the wrong purpose. It is pretty much mulch and nothing else. Since a fair amount of it is bark, leaves and twigs, it does not hold much value. Even in biomass boilers (and I mean industrial sized ones) they cannot burn the stuff, they need what is called "clean chips". It takes a better processor (massive chipper) to produce that which is a specialty of the forest product industry. The show Ice loggers is a great example of what to see regarding what is considered "clean chips".
I really don't think you will have trouble finding a source for your fine sawdust. Good luck!