Gearbox have formally revealed two new DLC packs for Borderlands 2: one of which adds a new vault hunter, while the other introduces a level cap increase and difficulty level. Details below.
First up, The Psycho Pack. This $9.99/800 MSP download includes a new playable class/character: Krieg the psycho. Described as a failed experiment, this new combatant will reward players for mixing it up in melee and taking otherwise insane risks. Here's some blurb, you blurb-lover you.
"Wielding a buzz axe and harnessing his psychotic multiple personalities, Krieg is a badass melee mauler with ranged attack capabilities that can rip foes to shreds with his deadly Buzz Axe Rampage action skill. Players can stack combat bonuses with Krieg's Bloodlust skill tree, live on the edge of insanity with the Mania tree, or engulf both enemies and yourself in flames with the Hellborn tree."
The Psycho Pack won't be included with the season pass.
However, the Ultimate Vault Hunter pack will be included for season pass holders, which increases the level cap from 50 to 61 and bolts on a third playthrough (the titular Ultimate Vault Hunter Mode). I don't know how much this will cost otherwise [UPDATE: About $5]