Have you looked at any of the packs made by Dan Cooke at Cooke Custom Sewing? I don't know the size of the Granite Gear solo pack, but he makes so many different shapes and sizes of packs, and all comfortable and extremely well-built.
Here is the link to the CCS Hybrid packs. The Pioneer is the most commonly used, but maybe the Explorer would work for you. I believe he also makes a short-torso version of any pack.
Good luck!