Are there any half-official repositories for CentOS 5 with Python 2.7?
EPEL provides only Python 2.6
I made an RPM for this a little while ago. You can find the source RPM here
ftp://ftp.pycopia.org/pub/python/RHEL51/python2.7-2.7.1-1TH.src.rpm
Just do the usual rpmbuild --rebuild ... to create the binary rpms. It does not interfere with the installed 2.4 version, it coexists with it. but you do have to put the specific version in your scripts: #!/usr/bin/python2.7. But if you use setuptools invoked with that version then it happens automatically.
Have you checked any of these repos:
Is it ok if you have the rpm instead of a repo (i.e. can you take care of dependencies if it arises?). If so, try phone or rpmfind. If none of the above helps, consider building from source tar balls. By far that will be the easiest.
You can try to get 2.6 srpm from epel you've found, extract spec file from it, change version number and rebuild it.
However, be carefull: there are a lot of packages depending on python 2.4 on el5 (like yum). You'll probably need to ensure that you are installing 2.4 and 2.7 at the same time or that you've rebuild everything depending on 2.4.
mod-wsgi -- it depends on python-dev, so you cannot use two mod-wsgi's simultaneously (I had to make a custom RPM for mod-wskg-python26) Not that I am aware of. However, you can find .spec files on the net to build parallel python versions where all the RPM files are named python27-whatever etc. Then the default python executable is still your vendor one, which should not be changed or you may break very important things, like rpm itself (I speak from experience).
Note that starting with RHEL5 (I have no experience with 6), rpmbuild will "precompile" python in any RPM. It's a known bug that they refuse to fix that it will mess up the %files section. Anyway, the problem is that the files will be precompiled with the stock OS python, which is really annoying because then you get "Bad Magic Number" errors if you try to use them. You need to change some RPM config scripts, but I don't have the info in front of me.
You can try my build adapted from Fedora 16: http://ftp.srce.hr/redhat/test/el5/x86_64/
Not that I am aware of at this time, but then again it would be prudent to learn a standard gunzip make install instead of relying on package managers.