max/msp isn't language. Second it's closed source, so no hope to "integrate" it. But you can have max/msp and a program compiled in blitzmax talking, through midi, tcp/ip or osc (this one you would have to code it from scratch).
If you are considering making an osc library for blitzmax, I am in.
If you are considering making an osc library for blitzmax, I am in.