interesting article and very interesting pictures. i do however disagree with the "upgraded" rpg or rpg-22 theory. i have seen hits by shaped charge projectiles that are with little doubt more modern then what saddam has to offer on a shooting range during my army time. it wasnt on composite armor, only on those good ol m48 and m60s who now serve as target dummies, but still i fail to believe that it would create a jet that would stay coherent till the other side of the tank. always keep in mind that tandem warheads are normal these days (even on many portable at systems) and that a HEAT jet quickly dissipates when travelling in "air". that is why israeli merkava tanks have the simply but very efficient method of having simple metal chains hanging from the rear of their turret to detonate rpg rounds prematurely so that the jet dissipates in the air before it reaches the turret/hull joint http://koti.mbnet.fi/~herrax/images/merkava.jpg
it might not be a railgun, although research is surely far enough in many countries to achieve such results, since noone with half a brain would actually go and send his precious research work to iraq and risk it being recovered by u.s. forces.
it might have been a next gen shaped charge warhead tested by some opfor nation, but i dont buy the rpg-x theory, since rpgs are more(rpg-26 and other LAW
style weapons) or less (rpg-7 etc) portable weapons. and to achieve above effects, even modern(and they are really more or less state of the art) western anti tank weapons would not achieve such a "spill free" hit and coherent jet.
there is plenty of footage out there of big (and the bigger the diameter the cleaner your jet, which speaks against the portable theory) at weapons with modern warheads hitting tanks. you will never see such a clean cut and rather unharmed outside of the tank and not skirts without any damage.