According to its description,
pandoc can convert between:
markdown and (subsets of)
reStructuredText, HTML, and LaTeX; and
it can write plain text, markdown,
reStructuredText, HTML, LaTeX,
ConTeXt, RTF, DocBook XML,
OpenDocument XML, ODT, GNU Texinfo,
MediaWiki markup, groff man pages,
and S5 HTML slide shows.
It will happily convert from ReST to LaTeX. The contrary though, will be harder, just as it would be with other formats such as markdown, because LaTeX is much more finegrained than ReST.
pandoc will convert basic things like
\verb and such, but don't expect it to do any advanced things or to be able to support LaTeX packages.
I've used mardown with
pandoc in the past to generate LaTeX.
pandoc allows you to include some LaTeX inside the markdown documents (and maybe also in ReST documents, I haven't tried). This would allow to do your matrixes while keeping most of the document in ReST.
That said, I ended up switching to full LaTeX when there were just too much LaTeX in my markdown files.