I think about the cheapest reasonable solution may be a T2i with the 400mm L f/5.6 and 2x Extender.
You definitely want the high density crop camera, and the 2x Extender, mounted on any 400+ decent quality lens, to give you about the most bang for the buck I can think of.
Not sure about scopes, etc...if you have something, it may be worth a try!


