Yeah, it won't be easy.
Diablo's idea of making a .NET app that creates a custom xml file is looking to be the best solution. The only tricky bit is that a couple of the hacks interfere with each other. Those may require some special case chunks, but otherwise it should be fairly cut and dry. Making it so that anyone can add additional hacks is going to be the hardest part, I'd say.
In the long run, however, it should make everyone's lives easier.