Have you considered 3D printing your master pattern with a Z-Corp rapid prototyping machine? This is a great way to quickly get master parts for castings. (See http://zcorp.com)
I have a Z-corp Z310 machine in-house and could print a part like for you for $125 plus actual cost of shipping. It could be ready to ship the next day after placing your order if ordered by 3pm. Also, the hole would be included in the part!
All I need is an STL file (easily exported from most CAD 3D modeling systems). If you can't export STL, I can work from IGES in most cases.
If interested, please PM me. Or contact me through my website at: www.touchstone3D.com