Not an answer, but here are the facts:
Pine bark fines is a common potting mix ingredient in Al's region. But not in the NW.

So if you locate a source, shipping fees will be sizable.

I used the soil PEP at Home Depot sold as soil condition in the green & white bags. Also a blue bag called garden prep. Worked for me & less acidic than the pine.

http://forums2.gardenweb.com/forums/load/contain/msg031028425011.html?22

Nice post by someone local trying al's mix. She uses reptobark, but she is also doing the gritty mix and not the 5-1-1.

Corinne, I checked out the soil PEP, it seemed a little overly broken down to me

Not sure what you're wanting to plant, but hope my experience helps you decide.

I used the PEP as part of the mix with potting soil for perennial divisions of creeping campanula, yellow corydalis, ajuga, variegated ivy, & groundcover euonymous.

I also used it to make a mixture for potting up bargain spring bulbs in large containers on New Year's Eve & topped pots with 2" of it as mulch for winter. The riot of color from these late planted bulbs is a bit a bit floppy now either from rain or lack of sunshine. Perhaps, the PEP isn't solid enough to hold the stems firm in the pots in the wind. :o) Either way, I plan to plant the bulbs in the ground after foliage dies back.

For my large cedar permanent containers I put bagged medium bark through leaf shredder to get fines for Al's mix last spring. The upright fuchsias are showing nice growth as are hosta, bergenia, carex, acorus, heuchera, & dwarf daylilies. I topped them with my homemade compost in the fall & removed the excess this spring. I don't plan to replant them for some time, so hope it works!