My local West Marine store had exactly the same topsider that George Murphy was advertising at a lower cost and sans shipping from TN. This is a very standard device available at marine supply outlets. The brand I found at West Marine and the one George was selling was the "Big Boy".
Incidentally, you might save yourself some trouble by knowing how much oil you draw out at each oil change (8 quarts?) and ensuring that the topsider you buy has the same or greater capacity.