Stay away from the P-40 unless it has fixed landing gear, you don't want your first experience with retracts to be with 90 degree rotating mechanicals however, there are a couple of ARF P-40's that come with "air" retracts. World Models just released a new 60 size Mustang with retracts, saw one fly today and was not disappointed, I had two of their 40 size P-51's and have two 120/80" P-51's powered by Saito 180's.
World also has two sizes of Spitfires of which I had the 60 size with a S.T.90. It also comes with retracts and uses a retract servo, they work great. I may get the 80 incher and put my Moki 210 in it, can you say "haulin ass"?
Great Planes, VQ, Hangar 9, Planes Plus, Giant Scale Planes, World Models and many others have warbird ARF's and most of them come with retracts of some kind.
Do a search of the "reveiw" forum and in the magazine review forum, they will answer most of your questions.