I'm wanting to purchase the FS128T, but am willing to wait for a good deal. Does anyone know of a good place to find demos?

Bass Pro is the only place that sells the Ascend FS128T brand new. For a demo you might check out these guys http://www.westtexaskayakfishing.com/

The bass pro shop in Katy has a small pond on it and I think you can coordinate with them to try one out there. Not sure but I have seen them with boats and yaks in the water before.
If you are looking for stability and a good price the FS128T cannot be beat. But it is heavy and turns slow. It does not cut through the water like the faster hull designs but what it lacks in speed and turn-ability it makes up for in the amount of room on the yak and the convenience of being able to stand for long periods.
For the price you cannot beat it. I put a trolling motor on mine and it makes a difference.
Good luck.

Make sure you are prepared to deal with the cumbersome loading and unloading of this boat. I had one when they first came out and I developed back and shoulder problems trying to deal with it. The dolly is a must. Best thing I ever did was sell that thing.

Before I got into kayaking I borrowed my dads and took it down the Buffalo River on a 3 day float. Best trip of my life, but the yak left a lot to be desired. Its like an aircraft carrier. Big, stable, and lots of room but hard to maneuver. Like "Mateo" said, loading and unloading is very cumbersome.

Its not terrible, but once I got tried other styles and ultimately ended up with a Jackson, it was a night and day difference.

Loading and unloading your kayak is all part of the experience, and a lot of folks don't take that important fact into consideration before they buy.

i got a trolling motor for sale if you need one