All of my parts have arrived. I will post some pics of the cast RP parts as soon as possible. They are quite rough but are usable. I may just order some of the trickier bits from Provantage. They produce all the printed parts on their commercial Stratasys® Dimension™ 3D printers in high-strength ABS Plus® plastic. They are pretty expensive compared to any other sources but they do this as a business, not a hobby. I know from experience that many factors conspire to drive prices up once you start considering commercial operations.
I attempted to order the drive gears and the x-carriage-lower_1off but their google widget told me that they didn't ship to Canada. An email to their contact address resulted in a very quick response from Nick Pace telling me that he would have it fixed in a day or so. I love good customer service!
This will probably drive the price of my Mendel up into "WTF territory" but I am past caring. I am having too much fun.