He sells kits for the well regarded 55mm f/1.2 and the 85mm f/1.2.
He also sells a kit for the 35mm f/2.8 TS lens.
The conversion is reversable and requires minimal skills. The adapter is CNC machined brass and includes a focus confirmation chip. He also sells a kit for any of the 14mm 15mm 17mm 24mm 28mm 35mm 50mm 100mm 135mm lenses.
His adapters may not preserve infinity focus; this depends upon the lens.
Tom's Digital Photography Info / tom@mmto.org