Bard 5/Dirgesinger 2/Bard +1/Virtuoso 2/Sublime Chord 2/Virtuoso +8
Useful Feat: Planar Touchstone to gain access to the Undeath domain.
Having a high Wisdom score (19 recommended, but even as little as 13 makes this worthwhile) and Craft Wonderous Item is also strongly recommended so that you can Spellstitch yourself (this one you should take to the DM, because ghosts are weird in their sometimes-corporeal-sometimes-not existence). Since you have access to the spells Desecrate and Animate Dead (3rd) from the Undeath Domain, you'll be able to grant those to yourself as SLAs and use them basically at your whimsy. At that point, you can switch the domain you get from Planar Touchstone if so desired.
Try to start the game with two levels of Ghost bought off, and then buy off the other two as you hit levels 9 and 12.
Song of Sorrow is useful because it's a ridiculously high DC effect that lowers Will saves, which can be combined with Harmonize (Races of Stone) to great effect when combined with another Bardic Music effect or a Will-targeting spell (or Possession).
Song of Bolstering is also amazing because of just how high it boosts Turn Resistance, and as an Undead creature yourself, you're going to want that in spades in case of Clerics.
The rest of the songs are, more or less, garbage. Songs of Grief and Horror have mediocre effects, but the fact that you have to maintain Song of Grief makes it absolutely not worthwhile, and the limit of 1/day on Song of Horror makes totally neuters it. That leaves Song of Awakening, which is good in theory, but relies on your DM throwing legal targets at you to be animated, and then mixing them into encounters with monsters powerful enough that you'd actually want to use this ability. Lots of potential, but not worth two more levels down the drain.
In any case, this setup allows you to utilize Requiem in a bit more comprehensive fashion than just Fascinating/Suggesting encountered undead. The 6th level of Bard also allows you to ditch Suggestion gained via Bardic Music in favor of Song of the Heart, just in case your DM rules you still need to meet pre-reqs.