Will you be hunting by yourself or with another person. If by yourself, you would want something at least 14 feet long, 16 if there'll be two of you.
If you know how to canoe, you don't necessarily need to go real wide, 32-34 inches for a solo, 36 or so for a tandem. I'm assuming you will be shooting from a sitting position. A canoe is rather tippy for standing, unless you add sponsons or other floation on the sides. A flatter bottom will give you more initial stability than will more v-shaped or rounded bottom hulls, but they won't be as fast. You'll also want a little bit of rocker for ease of turning on small rivers.
You might consider a used wood and canvas canoe. They're much quieter inside and out than fiberglass, kevlar or aluminum.
They're about the same weight as aluminum and plastic boats, heavier than kevlar, of course.