Well, I'm going to put some energy into seeing just how well one can build an Associated gear diff. Maybe put some of this schooling I paid for to good use instead of rotting in my cube . If i come up with something good, I'll let you know.
Oh, give me some objectives you think would be worthwhile. I already have an idea for a limited slip sort of arrangement, or a diff that gets tighter as you apply more torque/rpm to it.