If you're looking for the most scale realism, my suggestion would be to keep an eye on ebay and search for PILOT kits. There is a very scale 40 size Decathlon on ebay right, it's the green one I built. Giant Scale Planes has an ARF and an ARC which is based on the PILOT kit but will need some work to make it scale. Hostetler has a 1/4 scale and a 1/3 scale which are nice but not true to scale in my opinion. You might also want to look at the Modellbau company in Germany, they have some nice Decathlons too.