I'm often asked why Expandacraft doesn't offer seating on our craft, well, it's simple really, everyone wants something different. Because Expandacraft can be configured in so many ways and for so many different uses, it's impractical for us to stock all the choices. This gives our customers the freedom to choose what works best for their needs and buy it directly.
More about seating: When using a kayak seat on an Expandacraft, choose one with good padding and a high backrest. You can add Velcro to hold the seat in place on the deck and some seats can be riveted or screwed directly to the deck.
Pedestal seats: Mounting a straight pedestal on our decking is not advised, a 4 legged seat pedestal is much more stable and does not stress the decking material. Overtons sells one for about $25 and you can have it swivel too. You can simply set the stool where you want it and strap it to the deck.
Here are a few links:
Cushioned fisherman: http://www.amazon.com/dp/B00BTWANN2?psc=1