I suggested something (vaguely) similar a few months ago. The main problem is that I doubt the 'defense' would be willing to have such a decision be definitive (and if it is not, why bother with such a "validation"?) -- they seem to prefer to argue endlessly in their forum. Rajlich skipped the ICGA process [Riis implies VR found it "biased"], and I don't see any reason to think he would submit to judgement elsewhere.If ICGA would like to have their decision validated they should present their evidence to an independent group for review. It seems to me that the 'defense' has appeared ready to present their case so the situation and resulting decision would be more balanced.
I had suggested Jonathan Schaeffer as a suitable person to head such a review (as Ken Thompson has already weighed in), though maybe you want to go further afield. For instance, having the independent group be some slashdot boffins should suffice, as they would understand the coding (and open source) issues. But as above, I doubt that VR and Rybka Forum would go for it, probably disputing the "independent" nature of such groups. Also, if one can't find a gratis review panel (unlikely once you leave the CC circle), it seems fair for the loser to shoulder the great majority of the associated costs.