If you can find a reasonably priced used Weeres "water bike" with aluminum pontoons that would be the route I would go with.
The Paddle King boats look very similar from what I can see in your picture. We like ours.
http://www.paddleking.com/They are for leisure and exercise. For a working boat like esshup says, there are better choices, but the one we have is plenty stable to walk around and fish off of. We will likely at some point pick up a small two person fishing boat to supplement our boating desires.
