I have a used Gregory Whitney 95 in size large for sale. It's in great shape with the exception of some staining on the suspension system. The top compartment does detach and can be used as a smaller hip bag. I have pictures at:
I'd like $100 shipped for it. I'd also consider trades for a decent daypack in size large in the 18-25 Liter range.
If you are looking for a huge pack that has a great suspension system, this is it.