Hi all. Only been here a couple weeks but love POTN so far and now it's time to ask a question to the experts.....
My first digital SLR was, and is a 10D. I just ordered a 50D which will be here next week. I do tend to like the crop body lenses because much of what I do is bird and/or wildlife photography. I shoot a variety of decent glass, 28-70 L f2.8, 70-200 L f4, and a newly purchased 400 L 5.6. Excited about getting the 50D, and especially because we are headed to Africa for 3 weeks in May. 
My question is this. I plan to carry a second camera in Africa. In fact my 16 yer old daughter is really excited about shooting back up. However, given that this is likely a once in a lifetime opportunity (heck, every photo op has the potential for being a once in a lifetime event), I am second guessing the idea of keeping the 10D as the backup. Based on what the trip is costing us, as well as the new 400 L and 50Dthis month, I really don't want to spend a lot more right now, but what is my best "economical" option? Selling the 10D and buying a XSi or XTi? (Never owned, shot or even held any of the rebels.)
The back up camera will likely mainly be using the 70-200 L f4.
Thanks



