At this page presented set of XSLT stylesheet for MathML 2.0 to LaTeX translation. The XSLT stylesheet is expected to be used as a module for more general transformations. It is implemented purely in XSLT, that is they do not use any extensions.
Yet XSLT MathML Library exists at SourceForge: http://sourceforge.net/projects/xsltml/
Full MathML 2.0 is is supported