Could someone who has done this already with their jon boat, give me a rough estimate on how much it would cost to convert a standard jon boat to the one like in the picture. Stuff like carpet and the wood using average ply wood.

http://www.secretweaponlures.com/odf/images/odfquarter.jpg

A lot depends on how much quality of components is important to you and how long you'd like it to last.

you could probably do the whole thing with cheapie wood, cheapie hardware and cheapie carpet, etc for around $200.  More realistically, $400. 

I have about $400 or so in mine and I used all wood. Aluminum is better but that cost would have been about twice as much. I have a few pics here somewhere, I will see if I can find them. Here is the link to my boat.http://www.bassresource.com/bass_fishing_forums/YaBB.pl?num=1246719121/0

I now have the back deck done, not just a bench back there.

Interested in doing this myself.

What type of carpet should I be looking for.

You're looking for carpeting for use in a marine applications, specifically bass boats. While both Lowes and HD sell an outdoor type carpet that is doable, you'll find it's not the ideal carpet by any means. Mostly because it's a loop style carpet. Why is that bad? Lay a rod down on the deck with a treble hook crankbait on it and then try and pick the rod back up. Invariably the hooks have snagged and extracting them without tearing the carpet is nearly impossible and often, a run will be created where you surgically removed the bait from the carpet. Most of the bass boat carpets sold by a couple of the internet companies along with BPS and Cabela's are loopless carpet.

There are a lot of things that can change the price. If you want a lot of great info check out this site!

Lots of good stuff and good people.

www.tinsboats.net