Tubegroover,
If you're interested in SET amplifiers with more power than a 300b provides, the LM 518ia and Coincident Turbo 845 are serious built and executed choices. Yes they're heavy beasts and for good reason, major power supply and transformers to properly handle the demands of the high voltage 845 tube. I'd really relish the opportunity to hear these two A/B directly. I suspect that they are both truly excellent sounding SETs if you need roughly 25 watts of power. Both use the 300b as the driver tube, these are high value amplifiers when you consider the total package they offer.