James,
This question came up in another thread and I wanted you to know that you don't have to fly Classic pattern planes Full bore, pedal to the metal. My 40 sized Kaos is very docile and flies great at 1/4 thottle. What I think is most important is how you trim these planes.
For example -- if you set the CG correctly on a Kaos you should get very nice slow landings. If you set the CG aft of its center of gravity like they sometimes do on 3D planes it will likely tip stall as you come in for a landing as it will be tail heavy. If the balance the plane forward of CG the plane will come in hot.
Ok that said. You can always build a Tipo or Curare fuse and modify a Kadet wing to fit it and to slow it down. Won't look as good with a square non tapered wing but it could get you what you want. Later, as an upgrade, you could build the original wing and swap out the non-tapered for the new wing.
A thicker fully symmetrical wing will be slower. A Kadet style wing modified to fit a Tipo would significantly slow it down.
The planes Brian mentioned above should all have real good handling at low speeds if trimmed correctly.
Your question led me to check out some various wing thicknesses of several of Bridi's older designs based on the percentage of wing thickness to cord width and of Bridi's designs mentioned above the Sun Fli 4 has an almost 20% (19.12%) wing section (thickness). see red outline in table below
If you're looking for a kit the Sun Fli 4 from Blue Jay should provide you a slow flying plane as long as you don't put the pedal to the metal. Not as slow as a Kadet, but slow enough that you should be fine with it.
http://www.bridiairplanes.com/hangar/sunfli4.html The price for it is reasonable at $100 plus shipping.
Bryan