This is a good way to support the DIY community. Using a DIY approach will help motivate designers at actual companies to dramatically reduce their power level. The Parts Connection - Electronic parts for audio hobbyists. STF Electronics - Champ kit, Class A Amp kit Guitar amp kits at STF Electronics Special custom kits are available. Different capacitors and tubes are avaialble.
All kits are available assembled.
Champ Reproduction Kit Includes the parts for the amplifier, except the chassis, tubes, terminal wiring board, speaker, and cabinet. Class A Dual Stage Amplifier Kit 12AX7. See STF's page. Torres Engineering Torres Engineering . That site contains only a small sampling of their products.