I had my sump drilled by a shop on Mukulteo Speedway about ten years ago, but I don't remember the name or know if it is still there. You might try associated glass on Aurora (425 778-2174) in Lynnwood. I've had some tempered glass made there but I don't know if they drill.
Also try searching for threads on drilling tanks with a Dremel Moto Tool. I've also done this on my sump and it went pretty well. If you only have one or two holes it might be a solution.