High powered single end 300b recommendations

You might check out Manley. They have 300b mono’s you can switch between SE and push pull, 12 and 25 watts, respectively. They have a 300b pre, as well. 

If you want a high powered push pull 300b. Look at a canary  reference 8 300b s in each channel. They have smaller amps as well. Also look at the western  electric  new integrated  amplifier  is is single ended 300b s wired differently so the power doubles up. Both of those recommendations  are not for the faint of heart  nor the empty billfold.

https://canaryaudio.com/M3000.html

https://www.westernelectric.com/91e#spec

https://www.canaryaudio.com/GrandReference.html#:~:text=The%20Grand%20Reference%20is%20the,under%20Class%20A%20triode%20mode.