Still, there are some alternatives. Ospreys Atmos 50 ($199; www.ospreypacks.com) is an excellent big daypack (3,000 cubic inches of capacity) that comes in three sizessmall, medium, large. The large will handle torso lengths of up to 22.5 inches (torso length is basically the distance from the top of the hipbone to the base of the neck). That should be very close to what your husband needs. Gregorys large-size G Pack ($139; www.gregorypacks.com) goes to 21.5 inches, which also may be big enough but will be a bit of a stretch. The G Pack has a little less capacity than the Atmos, though, so it might be a better choice for a daypack (plus it costs less.)
Lastly, Arcteryxs Bora 50 sports the ability to handle torsos up to 23 inches, making it one of the "tallest" packs out there. Its a mid-sized pack with about 2,800 cubic inches of capacity and excellent suspension. Alas, its also rather dear at $245 (www.arcteryx.com). But a great pack!
Your husband will need to get into a camping store that has a wide range of good-quality packs, and try on several. I think hell eventually find one thats just right.
Check out Outside Onlines Backpacks Buying Guide for a look at the haulers to get your gear from A to B regardless of your body shape.