FWIW, I'm working on a new Fedora package (in fact, I'm using OTRS 3 already in a pilot system using my own package), which should also work for RHEL6 (and CentOS etc.) in the future (but if RHEL+EPEL has all Perl deps I do not know yet). I started with the old (Fedora 7) package, but that was completely crap.
It still has to be improved a lot. Unfortunately, OTRS' way of installing various kinds of files in one tree (sometimes even in one directory) does not make proper packaging (i.e. complying to FHS etc.) an easy job.
Something that would be interesting to know: would the OTRS developers accept using something like cmake to do their builds? If so, then it's relatively straightforward to use cpack to generate both RPMs and .DEBs (as well as MAcOS and Windows) packages automagically.