Wow, interesting post; thanks for sharing this.
I've read a bit about type 1.5 and assume that your doctors are testing to confirm that you are indeed producing insulin and that you also have Islet cell antibodies? Are you taking any medication, either insulin or something to help you produce more?
Carbs are important fuel, especially if you are active, but you are right to be keeping your blood sugars down. My sister is type 1 and we ride together so I've seen firsthand the ups and downs of balancing insulin/carbs/exercise; she's learning to do a great job with it. We've both been reading a great book called The Diabetic Athlete by Sheri Colberg that is really wonderful. It covers both type 1 and type 2, but it primarily deals with type 1 with some discussion of how type 2 medications can cause some of the same insulin/carb balancing issues that type 1 athletes have to deal with. It does a great job of explaining nutrition for athletes and how you have to adapt to that with diabetes. You might want to check it out.
Also, there was a great article on type 1 athletes in the NYT yesterday.
I would love to see tt1 in the TdF!
Anne