Thank you all for your responses. I did find a 45 degree prism at Igor's Camera in Cleveland. http://www.igorcamera.com/
Ok, here's the deal though. It was a great price & mint condition. Cool. However, when I started using the prism, one of the first things I noticed was that in order to open the latch on the film back, you need to take the prism off the camera because it's in the way!
Does this sound right to you regular users? It seems like a design flaw to me, unless I'm doing something wrong.
The camera makes awesome photos by the way, and I esepecially like the wide 40mm lens which seems to be distortion free.
thanks!