I can't find any cheap diamond hole saw bits to drill my tanks. If I find enough people who are wanting their tanks drilled, I will buy the contractor grade expensive-as-all-heck bits, and I will come and drill your tank for you. Or you can do it, while I watch. I will supply the drill, the bits, and the ring that holds the water for the bit.
As with companies that drill tanks, the risk of your tank breaking is yours, not mine.
Anyone interested?