hardware fixes (Slot A to Socket converter)
Socket A (Athlon TB) in Slot A (Athlon K7)
Slot A to Socket A adapter were never released to the public due to problems with certain VIA based mainboards. At the time AMD changed it's processors back to a socketed version this adapter was made available to mainboard manufacturers to test current board designs to comply with the new CPU. During these tests problems were identified that lead to the point of not releasing the adapter to the public. Only tested OEM systems (containing preassembled mainboard, adapter and Socket A CPU) were sold. So you might find one of these rare systems containing Slot A adapters.
The converter was only available for system integrators during migration phase of AMD processors.These were only intended for testing purposes during transition time. That's why you won't find boards with dual socket configurations as you do for intel Slot 1 / Socket 370.
OEM only & system integrators only versions of AMD K7 CPUs exist that come in Slot A format but have internally a LIF (low insertion force) Socket A carrying a Socket A CPU. This is a K7 Thunderbird in a Slot A package. So you might find one of these rare systems containing Slot A adapters.
During transition time AMD itself sold several Socket A CPU's packaged in Slot A (Thunderbird core / model 4). If you can get hold of one of these you've got what you want.
These processors can be identified by their CPU ID: 6-4-1 and 6-4-2
On top of the Slot case should be printed: "AMD-A650MTR51B C" and NOT "AMD-K7650MTR51B C"