Hey-Hey!!!,
including me, there are two other folks. One has already got his set of Iron, the other is waiting for the group buy on the output Iron.I have built with pentode front ends, but not exactly this way. I built a shunt regulator, and had g2 referenced to ground instead of the cathodes. The cascode experiments showed the importance of referencing the upper grid( the faux screen/g2 ) to the cathode node. I have contemplated a resistance loaded EL34 for this job in one of the high voltage amps.
The EL34 is a bit down the road at this point. The more complex cascode seems to be the better option at this point.
regards,
Douglas