David,

I'm guessing that you want a S&G design, is that correct? Also, how much does your son weigh?

One Ocean Kayaks has some great kayaks that would suit your needs. If you want S&G, check out the new Cirrus SLT.

http://www.oneoceankayaks.com/stitchglue/CirrusSLTtech.htm

If you don't mind building a stripper, and depending on his weight, you can also check out the Storm SLT.

http://www.oneoceankayaks.com/kayakpro/SLTtech.htm

The redfish Parr is also a great boat (I built one for my son) but even the 14' Parr might not hold your son's weight for much longer. The 14' Parr will hold kids up to 110 lbs.

Pedro Almeida