What sort of problems are you having with your current pack? You said it's not acceptable...is it a size issue or a function issue? I have a Tamrac Expedition 8 that I can easily fit more things in than I can possibly carry! ;) I love the thing! I can take the Hassy, both Canons (AE-1 & Elan7), film, filters, lenses, tripod, raingear, trail mix, maps, hair brush... the list is endless!
But there are times when unstrapping a backpack and putting it back on is a real PITA! I have a smaller Tamrac shoulder bag that holds the Hassy & my Elan7. I can't fit any other lenses in it, and I must strap the filter packs on the outside of the bag. No tripod holder.
I keep looking for the perfect bag too. So I hope you find one! ;)