If you follow vintage tube amp listings on ebay, Bob Carver shows up on occasion with hand built tube amp listings. Some of them have been fairly simple offerings but with unique circuit designs which he describes in detail. Others much more complex and high power. He goes into great detail about the design and construction - even describing how he hand winds the transformers.
The ones I have seen are no reserve auctions that have drawn a great deal of interest and bidding.
The ones I have seen are no reserve auctions that have drawn a great deal of interest and bidding.