The fine motor issues, dysgraphia and combined with dominance and what sounds like some muscle tone problems point to possibly Developmental Coordination Disorder/ Dyspraxia to me. How are his life skills like buttoning buttons, cutting with scissors, using a fork and knife? Bouncing a ball? Can he hop on one foot (do each foot) for at least 10 hops without falling over? Walk on a balance beam or a straight line (we use the grout line in our tile at home).
In my absurd amount of research over the past few months, I discovered that DCD often has a speech component as well. My DS doesn't look as uncoordinated as the literature made me think, he looks like a class clown, until you pay attention to the coping mechanisms and cover behaviors he has developed. He had been in gymnastics and swimming and wasn't the best but he definitely wasn't the worst.
You may want to take a look at this checklist- this helped us realize that our problem was bigger than bad handwriting and the inability to copy notes from the board
http://www.dcdq.ca/
