There's a paladin ACF at level 6 that essentially deathwards your mount in exchange for a weekly 'remove disease' (ECR pg 208)
[spoiler]
Warded Special Mount
The lightbringer paladin is a special, favored warrior of light.
The gods protect his special mount so that the powers of
darkness cannot easily defeat him.
Level: 6th.
Replaces: One weekly use of remove disease.
Benefit: In addition to the standard qualities of a special
mount, a lightbringer paladin's mount is immune to all death
spells, magical death effects, energy drain, and any negative
energy effects (such as from inflict spells of chill touch).[/spoiler]
Dunno if it's worth noting that paladins get a few very nice mount-boosting spells, such as golden barding (level 1 spell, +5-8 force armor for hr/level) and spiritual chariot (level 2, SC 202, creates a weightless chariot out of pure force...nifty on flying mounts, or as a portable wall of force, or simply as a pimped out floating disc for heavy treasure hauls).