I've done the 1st half of disconnecting mine (and it made a HUGE positive power increase on just a typical stock 1st gen GSL) but Ari up at Rotary Performance in Garland, TX told me it would clog it up with carbon. He said depending on the driving habits (really fast in my case) and the condition of the engine, it may be an average of 6k miles or 6 months. I haven't noticed any differences yet and it's been at least 2000 miles since I disconnected mine... I just need to get my new exhaust system in to cut the damn thing off. (the CAT that is)
Also, I've heard in these forums that it will "melt the cat" and clog it up and who knows what else, so, for what it's worth you know as much as I do (and obviously you know more about the oxidation and stuff that I'm clueless about.)
Good question though... I'm gonna be watchin' this thread closely.