Once upon a time I owned a very early Jeff Korneff 6BQ5 SE amp that was amazing. Years later, when it came time to sell it, I was in contact with Jeff Korneff and he asked me not to describe it as a Korneff amp, but as an early Jeff Korneff design as his later Korneff 45 amps were of a much higher build quality and fit n finish from his earlier offerings.
in the past few years, I’ve seen several people calling their DIY 45 amps “Korneff 45” amps although in no way did they even closely resemble the dual power switched Korneff 45 amps that Jeff Korneff built.
Having said that, here’s what I found on USAudiomart:
https://www.usaudiomart.com/details/650163139-ja-burgess-45-2a3-amp/
https://www.usaudiomart.com/details/650150535-james-burgess-pp45/
https://www.usaudiomart.com/details/650148370-45-tube-push-pull-amplifier-by-will-vincent/
https://www.usaudiomart.com/details/649928885-jeremy-fix-single-ended-13em7-tube-amplifier/
The last one is not a 45 amp, but I thought it was pretty awesome. Hope this helps,
Lou