I always thought of Don Cab as the mathiest of math bands. I still wack them on once in a while. Rodan too, plus their various offshoots. A mathy band that I came across in recent years is Ruby Falls (they aren't new, I'm just catching up) they're kind of like math Babes in Toyland.
Dazzling Killmen just popped into my mind. I had forgotten them and haven't thought about or listened to them in years, I think I will tomorrow, and see how they've held up.