I would think that you could get a “regular” backpack for a lot less $$$ and it would perform as well as those $150 options. I have a Kelty redtail 1800 (from Sports Authority on Rivers - they had a great selection of backpacks last time I was in there) and it would do everything you mentioned, for around $60. http://www.rei.com/product/780622
It seems to me that the “fly rod holders” are just normal side mesh pocket water bottle holders that are hyped up so that they seem “specialized” and therefore can drive the price point up. The Kelty has all that and a hydration bladder pocket, too. The only thing it doesn’t have are accessories on the shoulder straps that are accessible while the bag is on, but you could find a way to secure a couple of small fly boxes there easily, IMO.