I had totally forgotten that WS makes a 10' Tarpon, that one would definitely be a more manuverable option. However, after seeing the size of water you'll be using it on, I don't think the 12' will be too much boat to turn.

I found another option for you though. Perception is a very highly regarded Kayak mfg and they have one out which is pretty similar to The Tarpon 12 but goes for $580.
[url=http://www.kayaker.com/new/products/boat.asp?type=sit-on-top&ID=122:7a929]http://www.kayaker.com/new/products/boat.asp?type=sit-on-top&ID=122[/url:7a929]

I actually think Perception boats are made better than WS (after having sold them both) even though they are not as popular with the fishing crowd.

Here's a slightly longer one that's got a hatch and a Rudder for almost the same price as the Tarpon 12. [url=http://www.kayaker.com/new/products/boat.asp?type=sit-on-top&ID=123:7a929]http://www.kayaker.com/new/products/boat.asp?type=sit-on-top&ID=123[/url:7a929]

If I could transport it, I'd get the 11.5 for myself.