Heroes of Horror's first monsters are Bane Wraiths: incorporeal CR 8 undead with 8 RHD. Given the difficulty of rating previous incorporeals, this probably isn't going to be easy.
Bane Wraiths have decent boosts to what ability scores they have, a pretty good flight speed, +4 turn resistance, darkvision, and a couple of interesting special qualities in Empathic Sense and False Substance. The first is heavily roleplaying-dependent, but the second has a practical use in making 'angry mob syndrome' somewhat less of a problem. Detect Thoughts and Disguise Self at-will are useful, but not exceptional at these levels.
The wraithlike beings' primary weapon is a touch attack that can deal either 1d4 strength or 1d4 wisdom damage. Compared to the touches of greater shadows (CR 9) that's inferior, but the added versatility means bane wraiths can actively target lower scores, which presumably gives them an advantage.
Both attacks also have an additional boost: the wisdom-draining attack has a chance to go completely unnoticed, whereas the strength drain turns into constitution drain after a target's strength has dropped to zero.
As befits any incorporeal undead, those killed by a bane wraith rise as regular wraiths in a matter of rounds. Endless growing undead hordes unbalanced, yadda yadda yadda, worthy of an asterisk.
Ignoring the unratable spawn creation for a moment, I think bane wraiths deserve a LA of +0. Incorporeality is a powerful tool, as is variable ability drain, and the side abilities are surprisingly useful in any campaign that's not just hack-n-slash, but 8 RHD really limits the monster's potential.
LA set as +0* for now, but do discuss.