I saw videos of Styromax (another Oz company) building joints like that, and like Victorian mentioned, thought "no way in hell is that a strong joint!" The strength is in the skins and the glue contact skin-skin is very little.
But... if you make a completely torsion free subframe and reinforce edges with internal structure, and use the right glue, then it apparently works! Seems a bit crazy to me, but the proof is always in the result.
Couldn't you make any angle you wish using that method? With CNC it should be easy. Also, what glue did you use?