If no one is able to help, or if you don't want to pay for shipping and labor costs, the only real way is to do it yourself. I do have some patterns that I use for my 120mm fans; they are still being perfected, but are pretty close - usually one of the drilled holes is a little off, but the main hole itself is fine. If you aren't good with a dremel, find something similar to practice on. Or try cutting an 80mm hole first, inside of where the 120mm hole would be.