Just a plain, high quality amp, no need to be integrated. no need for volume or tone controls.
Email me on jcoulson@iprimus.com.au if you have something, and I'm open to considering any quality DIY project you have constructed and no longer want (appearance is of no concern as it will be housed inside the speaker enclosure) - but SS please, no tubes/valves and under 100W but definitely no less than 50W RMS minimum into 8 ohms. And, being in a confined space it will not have good ventilation so must not have high A biasing and run hot.