I think having a set of street tires, and a set of mud's makes the most sense,... trying to get the best of both, means you end up short on both,... If you are trying to save a few $ maybe check around for a used set that someone is trading up on. Make sure you have them checked well though. Thats what I did with my first set of Swamper TSL's. Got them with about 75% tread left, paid $60 a piece for them,... and at the end of the day discovered I was glad I didn't buy them new. Bought a set of MTR's instead for the trail. Love them,... for the trail,... and love my BFG's for the street.
Good luck regardless though.