Hello Myles

The example that you have cited encounters issues on every step along
the way - plastex, mathtoweb and odt.

I have tried my best to be useful here. 

I sincerely appreciate you exercising the LaTeX to MathML conversion
facilities included in Org. I hope we get robust LaTeX->MathML
converters *ultimately*. I see that there is plenty of scope for the
LaTeX to MathML converters to improve and mature.

This is going to be a long mail. Read on.