Thanks for the nice words!
When we came out with the Kaiju, we dropped the 2A3 direct-coupled option for that amp. So Stereomour became our only 2A3 amp. I really wanted to make it possible to upgrade it to the Kaiju level technology, so that we would have a flagship 2A3 amp. The level control upgrade matches the BeePre upgrade, the shunt reg matches the Kaiju, and the DC filament offers the low hum of Kaiju for situations where that is needed.
There are a few other possibilities allowed for in the design, but they are relatively esoteric and less cost-effective so they have not been tested, much less developed as kits. Yet. :^)