createrepo with delta for rhel/centos/epel

hi,
the current version of createrepo in rhel/centos is not able to generate
deltarpm packages. it'd be very useful to update it to newer version
which is able. currently deltarpm and yum-presto is in epel, but
unfortunately epel can't update packages already in the upstream distro.
so it's now a deadlock and the only solution is to update the in distro
createrepo:-(
at the same time i can create a new createrepo for myself, but another
problem that the latest createrepo requires at least yum-3.2.23 but
rhel only has 3.2.22. even though i try and it seems 3.2.22 would be
enough (build and seems to working) for createrepo-0.9.8-2. is there any
good reason to require 3.2.23? is there any good reason to update yum to
an even newer version?
thanks in advance.

-- 
  Levente                               "Si vis pacem para bellum!"