First of all teslin is a 23 foot jon boat with 4.5 inches rocker aft and a 29 inch maximum bottom width, 18 inches at the transom.

It is an unbelievably efficient boat, planing with 6 hp, but is a toothpick in regards to length/beam.

I think an interesting experiment would be to greatly increase the bottom width and leave every other dimension alone.
For convenience the increase would be 18 inches, resulting in a 47 inch max bottom width, or the maximum that can be achieved with 4x8 plywood without resorting to cross planking or having multiple pieces side by side. It is still very narrow for a 23 foot boat.

Tom Lathrop stated the most important figure to consider in a planing boat is weight per bottom area, with the lowest values being the best.

The wider bottom would massively increase the size of the boat, with realtively little increase in weight and cost and no increase in effort to build. The bottom area would be enormous allowing it to carry virtually any load on plane with a small motor.

I know full well I will be forgetting about planing with 6 hp, but planing with 15 to 25 may still be possible, and would be far better than anything of comparable capacity on the water today.

Figuring 500 to 600 for plywood, 300 to 400 for other wood, 200 for fasteners and chemicals, 180 for paint and oil, 250 for hardware, and 180 for electricals and lighting, 6.25% tax and 160 for registration, title etc legal stuff.
budget $2500 for some leeway, still a cheap boat for something that big.
Power would be my Fastwin 18, and if I ever get in a hurry and have excess money then a yamaha fisherman commercial 40 would seem to be a wise purchase.

free study plans for the original here plus some good photos: http://www.scribd.com/doc/2897271/Teslin