Trailer Siding

I am in the beginning stages of building my first teardrop. I was thinking of using MDO (Medium Density Overlay) for the sides of my teardrop. I can get 4 X 10 sheet of 1/2" for $45 each. My idea for the wall construction was 1/2" MDO, 1" x 4" frame with 3/4" isolation & 1/8" birch on the inside. That would give me a 1 3/8" wall thickness. I was going to paint the exterior with oil based paint. Anybody out there ever use MDO?