Catfish, at least the hull shape presented, is based on the Alligator, a 42' LOA paddle wheeler described in 1911 in The Rudder ( http://books.google.com/books?id=3Ko6AAAAMAAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false ).
Like Alligator, Catfish is just a large flat bottom boat with some fuss to keep it from sinking into the muck should it dry out in muck. Engine placement would be similar to Alligator and a chain or belt drive would be employed.
With a beam of 7', 7'3" over the rub rails, it would have a LBR a hair shy of 3:1. Draft would be essentially 7". Overall length is 25'11". Displacement is just over 2,800 LBS. Per DelftShip's drag estimates it would require just under 4 HP to push the boat to 6.3 knots.
Larger versions should trend towards a 4:1 LBR and, naturally, somewhat greater draft to permit better accommodations (Alligator from The Rudder would have 9" draft).
Though not intended for rough water, the flare forward and rub rail should help keep the boat dry if a powerboat sped by much too close and much too fast.
It may be useful to have an off-center centerboard to help keep it getting blown about too much by the wind.
No attempt has been made to represent the light weight cabin structure that would be used. Likewise, only the outer diameter of the wheel and the inner clearance needed for whatever wheelhouse used is shown. Ditto for whatever rudders/monkey rudders would be mounted.
The oblong shape of the wheelhouse clearance outline is due to the desire to be able to raise or lower the wheel by up to 4".
Raise: to better facilitate launching from or recover to a trailer ... there's no buoyancy back there being something of the thought.
Lower (and raise a little too, I suppose): because it would be a real annoyance if the best operating depth of the wheel were something different than what it just happened to be if built at a fixed height.
Also, from what I've read, by lowering the wheel you can trade off efficiency for Bollard Pull, which may help in fighting a current someday.