I ended up making a 3D model of the fractured elbow, in case anyone is interested. This should be able to be printed with an online service for about US$9 shipped (or $92 if you want to get it in titanium 🙂 ).
Note that I have not yet tested this. I will report back on how well it fits. At any rate it could be sanded, etc.
I mimicked the original almost exactly, with a little more curvature to the internal windway and some other less significant changes. The diameters and tapers and depths should match exactly.