Great idea. You could probably use a long 3/16 drill instead of the holesaw to make this easier to handle since all you need to locate is the pilot hole. I may make one up to drill the hole I need, just to try the idea. I bet the waste chunk you get out of the holesaw is a good fit in a piece of conduit. Drill out a couple holes in some hardwood or thick plastic for the plugs. Epoxy them in the conduit.
