pine bark fines are commonly available in the southern states. Up here, you're more likely to find fir, hemlock, maybe even redwood is more a California sort of thing.

You might try Bakerview Nursery. Here's a link to their webpage on Bonsai supplies: http://www.bakerviewnursery.com/BONSAI-.html

Thanks all. I was able to find some at my local Lowes. They finally got a shipment in.