RHEL/Centos 4 are still sitting on 1.99_16, which probably isn't helping matters.
Debian stable: Package libapache2-mod-perl2 1.999.21-1Which is a version BEFORE the big namespace change, and so basically not usable.
Unfortunately Debian's three year release cycle, and 'never ever change stable' policy, means that Debian will not have a stable mod_perl2 any time in the near future.
It is not even available on Testing and Unstable :(