Russell, that item looks as though it is in "Popular Mechanics", I'v got quite a few of their articals, but not that one.
I only occasionally use a slitting saw, and I make up a table of MDF, It gets clamped in the tool post, and fed into the saw, forming the slot in the table. The local furnature factory has a large box at the gate with more MDF than I'll ever need. Ian S C