The Osprey Soelden 32 may be worth a look - It will not have the faff around opening the bag up as it has no extra straps at the top to get in the way. It is the newer version of the Kamber I believe.
I didn't try the Soelden as I could not get it in a colour I liked - they are very thin on the ground. I am also not convinced that the top tripod strap would be any better than I mentioned for the Kamber - it looks like it may not stretch around the bag but I have only seen photos and am not 100%. I have only seen it in one size as well - so may be too short???
Dave.