Honestly, I feel like the solution is making him more EXPRESSIVE, and not actually "happy". Some type of moving facial parts. Eye-brows, as eye-brows can be extremely expressive, should at bare minimum be movable. This way it will be easy to rend the Digi-Man in a plethora of different poses with the correct expression for the occasion.
Just my two digi's.
That said, what I didn't say was:
I have done some modeling in my day, and bman3 did a great job that surely took considerable time
Don't let my nit-picky-ness persuade you that I don't think it's super-cool, very professionally done and appreciated