I've been told by people who actually write tuning software for a living that GM V6 applications have litterally hundreds of different OS's
You had to be told this? Its pretty stupid obvious as there are about 5 versions per model year, per model trim, per vehicle make... so do some math on the 10 year run all these cars made and its obvious that there are many of them. Luckily for us the templates are really similar to the point you only need to create a handful of maps to fully adjust all 400+ OSID's.

Care to give me the statistic on how many maps exist in CATS to support however many osid's it does support? I know there are about 13 in DHP that support 96-05 model year files.

The reason why you don't see the Cat Diagnostic check in Tiny Tuner for your 04 file is because it probably wasn't added for your specific 04 PCM's OS
Tiny Tuner is all but worthless, in my opinion
So add it yourself... Its a FREE program that is also open source... Try adding it in HPT lol.

I dont see you releasing your own open source tuning software, so why are you talking shi! about something that many people worked hard on to release? The truth is there is as much functionality in TT as there is in your overpriced cats software, and its a fact that there is more supported values in TT for one of the 02 map files.