WowAce

I've always liked the way Pitbull's visual heal displays absorbs, but there is no equivalent setting for negative healing absorbs that I have seen. This often makes it difficult to decide how large of a heal to cast on a target with a negative absorb, since these are typically only displayed with a debuff icon and no indication of the remaining absorb value.

The current (positive) absorb bar extends a purple bar to the right from the right end of the current health bar. A good implementation for negative absorb could be a similar red (customizable w/ color picker?) bar with reduced opacity (50%/opacity slider?) that extends the opposite direction, overlapping the current health bar. It would also need a max width (i.e. no more than 50% of the original health bar's width + the width of the current health bar) to prevent it extending too far in cases of negative absorbs significantly larger than the unit's current health.