Actually, when you use 2 pledge moves in the same turn, the second one gets its BP increased from 50 to 150. That's pretty damn good. Swampert+Infernape seem to be the best candidates to use this combo. It's probably not worth building an entire team around it, but I'm pretty sure both of them are viable in doubles and can spare a moveslot for those moves. Keep in mind that Rock Slide hits both opponents and Infernape is quite fast, while Swampert is bulky and learns Icy Wind, which is helpful if you're planning to abuse flinchaxing. As a bonus Infernape learns Fake Out while Swampert learns Wide Guard.