Chomsky has mentioned the possiblity of genetic variation in UG, but
it's certainly not on anyone's priority list. Except that there is
a family in Montreal, being studied by someone called Myra Gopnik,
who apparantly lack the ability to manage grammatical features such
as tense and number, and are currently the focus of considerable
interest.
The idea of motor programs as a basis for syntax strikes me as quite
intriguing, but in a preliminary unguided foray into some of the
literature I did not get very far with it.
Avery.Andrews@anu.edu.au