I really appreciate the effort InsaneNutter. I've been waiting for someone to do that for about a year

Yes the installers do work with the modified emulator for Jtags as I stated in an earlier post. I've been working on converting the update work on a jtag without crashing. The issue is that you can't launch any second item from a CDX menu without the emulator crashing. It's also why the XBLA launcher doesn't work. I've tried a few things but can't get CDX to launch a second item. So to make the updates work on 360s, they'd need a separate installer, which I do have working. It's just a matter of taking the time to create 40 or so extra installers.
I would love to get my hands on another copy of the MM3 DLC. I can't find what's wrong with it, just like I can't find what's wrong with the Fight Club stuff. I think they might require a live profile on the xbox. I don't even have a copy of MM3 anymore to test with, I had to trade it in to get other games. I do have the newest version of everything from Halo 2 though, including the last map updated in 2009. The original installer has the 1.5 update so I will have zero issues making it work fine for you.
The project is not dead, I've just been distracted with other things in real life, in too much pain to work, and too busy to really get into it. My next run through it will be my last, in which I will update all the installers to the new style, add extra title update installers for jtags, and finish building installers for all the remaining missing DLC I still have (which isn't much other than sport updates).
If you have any questions or contributions, it's really time to get them to me. InsaneNutter please contact with me a way to grab that DLC off you so I can check it over. Thanks for all the support everyone has given myself and AmyGrrl on this project, it's the only way we can get the missing bits these days.