I just spoke with my local Festool rep today regarding this issue. He said he expects a peared down version of the T15 set within the next 3-4 months. I already own the C12 with all the different chucks, so I didn't really need them either. Ultimately, I bought the entire kit today. My logic was that if I have two drills with one set of chucks, someday I'm going to be on a jobsite with my T15, only to realize that the chuck I need is back at the shop in the C12 systainer. It's the same logic that prompted me to purchase an extra power cord dedicated strictly to the boom arm assembly. The first time I packed up my saw and left the cord attached to the boom arm was enough reason to own two of them. I figure the same may hold true for the chucks.
Regards,
TC