Our girl is a mutt too, LOL, the Humane Society called her a border collie/lab mix if I recall correctly.............but honestly, I don't see the lab in there at all.
You can see why I asked about Trixie, this is our Phoebe. Trixie looks a bit heavier, (Phoebe stays around 38 lbs) but they share lots of similar features in my opinion.