For a 64-bit CentOS, it might be worth trying this build: http://sonicvisualiser.org/pre/qm-vamp-plugins-0.6-svn20100629.x86_64.rpm
As the title and date-stamp suggest, it was a build from the private QM repository in June made for a particular application on a particular machine -- I'm not totally confident about the details of which machine or application, though!
With regard to source code, the answer becomes more interesting -- the QM plugins have so far always been closed-source, but we have just during the last month published the source under the GPL.
This hasn't been announced properly yet because no binary release has been made from the new code yet, there is some administrative work to do with updating the site for the new code location, and some details like build instructions are lacking, but the code is available: http://code.soundsoftware.ac.uk/projects/qm-vamp-plugins
Note that the plugin code depends on another library, also hosted at the same place (it's linked from the intro on that page). Currently, to build the code, you will need to pull both projects from their Mercurial repositories, use "qmake" to build a Makefile from their project files, and then make. The use of "qmake" (the Qt build tool -- even though none of the actual code uses Qt) is an untidy stopgap -- sorry -- this is one of the several things still to be tidied up.