Ok well I did it, I rebuilt the index buffer, and Rob I'm pretty sure is right. No discernible differences in speed. That's because, i'm assuming, the index buffers are actually the same dimensions (but i'm not sure because I don't know how to see a jit.gl.model's index buffer, but we don't see extra faces being drawn, so it should be the same. perhaps the only difference is jit.gl.model's index buffer is listing all vertices just once [rendundant included] whereas mine will reuse vertices, since it eliminated any redundant ones). With the low poly icosphere, there is 20 faces, so each one needs 3 vertices to define the face, which gives a 60 vertex index buffer. If you see the dimensions of its original matrix output, that is also 60.
I guess I also didn't try piping my icosphere model into a mesh before, but that gets 60fps just fine.
But in the spirit of sharing, here's the new vertex reduction patch which also rebuilds the index buffer. If anything, it's fun watching it create all the faces. Load in the icosasphereHi and have fun watching it build 1620 faces.
inside the subpatch vertexReduction is the index rebuilder on the right side of it. it's kinda a spaghetti monster, but works. let me know if i need to explain any of the mess.
enjoy.