Dear John,
Yes in my perspective, the Pioneer anomaly is originated by a fully new unexpected phenomenaa a copy of what I call galaxy Anchor Black Holes:
Stellar Anchor black holes.
see my blog article:
New paradigm Galaxy Anchor Black Holes (GABHs) outside Galaxies, the origin of dark matter Halos with point sources see:
http://migratingblackholes.blogspot.nl/2009_10_15_archive.html
see the text: with image of the sun:
"At the same time we may assume that our sun is the remnant of an open star cluster, better: our solar system is the remnant of an open star cluster created by two "STELLAR ANCHOR BLACK HOLES" (SABHs) and the result of a former Herbig Haro object!!"
This NEW black hole model is even the base for my explanation of the so called pioneer anomaly, bacause it influences the whole gravity system around the sun.
See perhaps also:
http://en.wikipedia.org/wiki/User:Leo_Vuyk