Why not get the best of both worlds and use 2 pots?
In one pot, prepare the pasta by boiling in lots of water.
In another pot or saucepan, prepare the thick "pasta water" by boiling a little pasta with very little water. This saucepan will now have the thick "pasta water" that you are looking for.
Simply add the thick "pasta water" to whatever sauce you want, and then add the sauce to the pasta!