Looks good. I'd buy some WW-2 military decals. After all it is silver with a yellow tail similar to some Mustangs. Just be careful with the gray and silver colors, they can disappear in the sky really easy under the right conditions. They can for me anyhow.

Retracts wouldn't be impossible but I'd definitely beef up the wing. There is no structure there at all to support even fixed gear. If you like the WM planes, take a look at the Rambler 45. It flys great and comes with factory installed retracts. I've been in the process of re-covering my Rambler for a few months. Other projects just seem to get in the way. Eventually it will be Cub yellow and purple.

Also, flip your main gear around so it angles back instead of to the front. It will make the plane nicer to land. I did it on my old Mach-1 and it worked well.