The 1/2A Sterling P-38 has been reproduced by Dave Cowell of DPC Models/AeroWerkes. I know he was taking some time off, but is starting to cut kits again.
You want to look at his Short Release Kits (SRKs), which are short kits with plywood wheel blanks, plywood bellcrank, and square stick leading edges.
I have one, and it is pretty faithful to the original.
What kind of engines are you planning on? Reed or rotary valve? Scale, semi-scale, or sport? Built up or all profile, slab wing?
I'm a sucker for twins, and have been collecting plans.
This is twin Norvel .074s.