My attempt to get a saddle pack from both Carousel Design Works and Epic Designs failed miserably--totally my fault though, giving them such short notice. That said, I've been in contact with Wayne who helped me out a great deal and have the Tubus Fly rack on the way! He is confident that the quick release kit will give me the ability to not only mount it on my Tarmac, but also give me enough heal clearance. Luckily, the Fly rack was my last major purchase before the trip in mid-June (I tend to get anxious about hemorrhaging money!).
Thanks for all of your advice! I'll post details of the trip upon my return.