Mike did you get anywhere with that pointer to the Canadian shop over on rcgroups? Your kind of getting the same advice in parallel on both forums.
I can't remember your motor size, but there's also a company called mfa over here who do motors and mounts, component shop also sell mounts. Considering most motors we use are "standard" can sizes there's usually a mount somewhere, or with a little imagination the mounting holes can be filed or reamed to size, or make an adapter plate to suit. You may not find an off the shelf mount for every motor simply because of demand, and easy enough to make "DIY" so they're raylored for about 3-5 commonly used motor sizes. As a living room table top modeller I try to modify something close as no workshop to use. Have to say though there's many many ways to mount motors and each to their own as long as it works though my pet hate is seeing jubilee clips wrapped round them, or gluing motors down!
The rcgroups thread recommendation was to use the dog bone joints common in the US. My one and only experience of them was they wear out, even when aligned. It's perfectly normal to use double huco joints, but still align as best you can in first place!