GetUnitAbilityLevel()

So, the native GetUnitAbilityLevel() is used not only for getting the level of a specific ability for a specific unit, but also for determining whether or not a unit has a buff, correct?

Is it possible to manipulate this in such a way that it will return the level of a buff that a unit has? Or will it just return 0 or 1 depending on if the buff is present or not?

Can one use SetUnitAbilityLevel() to set the level of a buff in a similar fashion?

Nope.

Because one-word answer rawk, it will always only return 0 or 1, for has/does not have the buff.

Damn. And you can't set buff levels, right? That'd just be too useful.

No, you can't.