Sigma's 70-200/2.8 HSM II is $949. That plus a rebel should get you going for as little as $1,500.
It would be a shame to lose the Tamron 17-50/2.8 on a stabilized body (The stabilized version for a Nikon or Canon body isn't as good.) so maybe you could keep the Pentax at least for that.
- The lens is the thing.
- 'Full Frame' is the new 'Medium Format'.
- "One good test is worth a thousand expert opinions." - Tex Johnston, Boeing 707 test pilot.