Do rogues or ninjas deal sneak attack on comabt maneuvers like trip or disarm?
Negative.
Sneak attack damage only applies when the rogue/ninja is making an attack, and the target is denied his Dex bonus to AC (yadda yadda blah blah), etc.
Trip and disarm don't directly deal damage, and aren't even technically "attacks," per se; they're combat maneuvers.
But I think your real question might be if you have a weapon that has [trip] and/or [disarm] in it's descriptor, then can you attack with that weapon, and deal sneak attack damage, and do a trip or disarm combat maneuver with the weapon. Is this what you're wanting to know?
I´m using a whip +1 Dueling FG subtle (like sword of subtetly), what ends on getting +26 with feats and traits included or +33 if flanking or invisible/hidden on trip for a halfling with weapon finesse.
The question is actually if i can deal sneak attack damage with trip or disarm combat maneuvers, but seems like no, what is ok.