This has probably been done to death, but here goes....
I currently have a LowePro Slingshot 200AW, but i'm looking to upgrade it to something a little bigger (i'd like it to be able to take a camera with 400mm 5.6L attached, but this isn't a must), with 2 straps (i find the single strap puts too much weight on the one shoulder), and also somewhere to fix a tripod.. Any idea's? I am on a budget, but there's always the second hand market, plus i'll probably sell the Slingshot. 
Cheers
