Creating Custom Fedora/CentOS ISOs

I've been working on creating some custom Linux ISOs and have recently ran into some issues. Originally, I used bootcdwrite along with some scripts for create an ISO of the running config on a Debian server. Now I am working on some Fedora/CentoOS/Scientific Linux ISOs and haven't had much luck doing the same thing. I've looked at quite a few forums and people normally recommend revisor/pungi and clonesys. I've tried clonesys a few times and have never gotten the ISO to boot correctly for me. Revisor works fine as far as spinning the images and adding/removing specific packages, but it doesn't (or I haven't found out how to yet) do the customization I want. Ideally this is what I want to do.

1. Install Fedora/CentOS/SL6.
2. Install new packages, change some files, modify iptabloes, etc.
3. Run a program to copy the running image into a bootable ISO.
4. Be able to boot the new ISO and act like it's a new setup (ask for DHCP info, password info, etc.) but once that is done, it will have all of my custom files and configurations.

This is exactly what I was able to do with bootcdwrite on Debian. I got everything working and configured the way I wanted it, ran a few script to remove tmp files, users, etc. to get it into a "raw" state and then converted it into an ISO.

From my research as of now, I see believe that Revisor is my best bet, I just have to figure out how to make it copy my running config with custom files instead of just modifying the packages (or maybe it does and I'm just not aware of it). That, or maybe I could use a more generic tool such as mkisofs.

Thanks in advance for your help.