So I am a tad on the large size. I am about 6'1 and 340 lbs. That is not my problem tho. I have 54" shoulders which I think is where my problem arises. The reason I bring this up is cause I found a few back packs at a couple local places and all of them are too small. I do alot of walking when I fish rivers and streams and would love something I can strap on my back pack a bunch of supplies and keep on fishing.

Any suggestions would be great.

This is gonna sound strange, but my son who's 6'6" @ 280 has used this backpack, it's actually a surfers backpack to carry a wetsuit ect..Now I use it for fishing.. ;D

Anyways..here's a link, you may want to call them to confirm that it will fit you. Kinda spendy, but well worth the $$$ imho.

http://www.shoponeillusa.com/product/Mens/Backpacks/PSYCHOFREAK/pc/673/c/0/sc/775/198583.uts

I'm 6'4" 230lb with 52" shoulders, so I somewhat feel your pain. The most comfortable pack I've found is actually an old US army ALICE pack. Cheap, durable, and TONS of room (especially the large size). It is an external frame, so it may not be for you.

I'm a big guy as well 6'3" 260.  I bought the Okuma backpack from Walmart.com.  I really did my research and looked at bags up to $200 and the Okuma was the best one ($50 I believe). 

That being said, I should have thought of an Alice pack, that would have been perfect.

I cant believe I didnt think of a Alice pack. I go into the Mil surplus stores all the time.

  Just be careful. Sometimes Mil-surp store charge WAY more than they are worth. I found mine (med.) for 25$. I'm also trying to figure out how to mount pvc rod holders. I'm sure there is a way. One other thing you can do. If you want/like a hydration bladder...

You can pick that up at walmart for around 10 bucks. Drop it in an outside pouch, Throw a velcro tie around the strap to hold the tube, and there you go.