For effective cutting of wood with a smaller blade the RPM of the blade has to rise. An 8 inch table saw for flooring works well with a 3600 RPM direct drive motor. But by the time you get down to a 4 or 5 inch blade you want the RPM to be up closer to 7000 to get a nice clean cut.
I've looked at the same idea myself but so far I've only found saws which turn at 3600 RPM. Also they would require a new top glued or screwed to the existing top so the wood doesn't fall down in the water draining grooves. So all in all I've let the idea simply pass for now.
If you do try it I'd suggest you look at the finer tooth metal slitting saw blades. My plan was to use an adapter to let me run with a thin .025 or .032 slitting saw blade of 4 inch diameter so I lost as little as possible to the kerf when cutting strip stock.
I see that Home Despot
has a cheapie for only $65. I may just need to look at this again even if it ends up just being a stop gap solution for now. Actually I've got some tile work ahead of me so it would be a good investment anyway.