Jens Osbahr has written an excellent article there, he updates it as well. Essentially his approach is similar to Ilford and May & Baker in adding a silver solvent to an existing product. Many commercial labs used May & Baker Suprol developer with Thiocyanate added, and the company wrote an excellent datasheet/manual with comprehensive data on the parameters for reversal processing in a variety os machines and also small scale use, it was particularly good on trouble shooting. I have a copy somewhere but everything is boxed away for moving, and I couldn't find it on my last trip back the UK.
You can usually get dilute Sulphuric acid and permanganate from most chemists/pharmacy shops. Permanganate is used as a mouth wash at dentists, and concentrated Sulphuric acid is often sold for unblocking drains, and of course topping up car batteries. You could use light reversal instead of adding Stannous Chloride, the Sodium Thiocyanate will be slightly harder to find.
Ian