Hi All,
There are a few errors in some of the turning numbers being thrown around here. I suggest you read this very informative threads (part 2 link is in part 1) for more details
http://forums.ddo.com/showthread.php?t=167986
A summary
To destroy undead you have to have twice the effective level as HD of the undead.
My best calculation as to maximum effective level is
Cleric Lvl 20
Feats Enhancements +4
Item (Seraphim or Orb) +2
Seek Eternal Rest +4
So Effective level =30 - Destroy undead of 15HD or less
I have not TR's my cleric yet, so I cannot speak definitively on the Past life feat, but all evidence from descriptions and other threads is that it adds +2 to your effective level
So Max I suggest would be
Cleric Lvl 20
TR x 3 +6
Feats Enhancements +4
Item (Seraphim or Orb) +2
Seek Eternal Rest +4
So Effective level =36 - Destroy undead of 18HD or less.
I won't go into the calculations for Highest HD and Number of HD effected as this is done in the attached threads in detail.
Regards
Wolf