I don't think it is Agency specific as I called a small independent agency in Irving, TX and they were able to pull the fare up (as both Orbitz and Expedia were).

I think perhaps my original assumption that SPN had something to do with Worldspan is probably incorrect, though It is clear that the fare seems to be published only in Worldspan at this time. The fare is simply not available in Sabre. I looked through the fare listing myself and had the AA agent try to price that specific fare basis.

I suppose this could be a glitch, but I find that a bit hard to believe.