If you're asking for highest hit ever you'll get completely bogus numbers as this will differ greatly based on the enemy at hand. During RoI my champ was scoring a 25k dev hit with RS which would be insane in most cases, but if you consider that it was in Draigoch Phase 3 (where he has +200% incoming damage) it's not that impressive anymore, level 100 chars might reach 50k or more in that situation now. Training dummies on the other hand will limit your damage potential as you can't get all buffs/debuffs normally available in a raid for example.
Used to play: 85 Champ / Captain / Runekeeper / Guardian, Guild Master of everything but cooking.
Playing now: Hellcat / King Tiger / GW Panther / IS / KV-5 / M4 Sherman and more