Hello,
Maxima 5.12.0 release candidate 1 is tagged in cvs
(as version-5_11_99rc1; I straightened out the cvs problem)
and there is a tar.gz file and rpms in the SF file manager.
http://sourceforge.net/project/showfiles.php?group_id=4933
Please give it a try if you can. There will probably also be
a Windows installer soon.
HTH
Robert