Would you consider the smiter to be making those damage rolls, or is it a condition on the target which is doing so? That's the obvious dividing line. I'd think the latter for being on fire or bleeding in most cases. Some spells might be exceptions.
I would not apply smite bonuses to conditions.
As a swift action, the paladin chooses one target within sight to smite. If this target is evil, the paladin adds her Charisma bonus (if any) to her attack rolls and adds her paladin level to all damage rolls made against the target of her smite.
A creature that is taking bleed damage takes the listed amount of damage at the beginning of its turn.
But what isn't clear is who makes the damage rolls in this case. It happens on the target's turn, so does the target roll the damage, or the attacker, or the DM? I've never seen any consistency with this through multiple tables, but on average, I've seen the target roll the damage more often than not. So, I'd personally rule that it is not the paladin making the damage roll.
I think it is a stretched reading to include the bonus damage on bleed effects, on fire, etc. The bonus damage is added to the attack damage roll with whatever weapon the paladin is making, and no other rolls.
Unless someone wants to suggest that damage from the party barbarian also gets the paladins bonus damage, as does the wizards shocking grasp, etc. I mean smite evil does say
...adds her paladin level to all damage rolls made against the target...
And not just all damage rolls made by the paladin.
Or should we also suggest that a paladin who bull rushes an opponent into a spiked pit trap gets to add the smite damage to the falling and spike damage dealt?
e.g, the smite damage applies to the paladins attack in so far as it applies immediate damage as a direct result of said attack. Any additional rider effects, side effects, etc, are separate from this.