Just as an FYI: Haversacks were not a civilian item but a military issue to carry rations, plate or bowl and utensils.
Certainly some haversacks went home with the soldiers when their enlistment was up, but not that many as they are commonly listed on regiment and militia returns. These returns are the equipment handed in by the militia, company, or regiment as it replaced old gear; was reassigned to another area where replacements were to be issued; or were mustered out of service. They were commonly made out of linen as cotton canvas was not widely available yet.
Ships sails were also made from linen canvas (not cotton canvas) and were naturally off-white in color. Lots of linen bags of various configurations in use from small drawstring bags up to backpack size. Shooting bags were commonly made out of leather. If you want something other than leather, following the example that Stumpkiller displayed of his homespun bag would be OK. Leather stood up to hard use longer than anything else and was commonly and easily available, which is why it was so widely used.
Twisted_1in66 :hatsoff: