Q: What class would be best to gestalt with a White Raven Warblade? Marshal?
Depends on what you want to do, I have been on a marshal kick lately and it's really nice for high cha builds, but warbalde is ussualy high int.
However if you have good cha, having the aura that adds dmg to charge attacks, a fly speed (so you wan make a diving charge) and a lance will let you add tripple cha modifier to damage. Add pounce, and you opponent is in for a world of hurt. Oh and incidentally you are buffing the rest of the party at the same time.
However you don't want too many marshal levels, probably not more than 5 (2 major and 3 minor for flexibility) usually less, although the grant movement ability is nice with the charge aura since it allow setup for the charges.
If you relent a bit on the no caster add a level of cloistered cleric followed by some prestige paladin levels, adding cha to saves and another bunch of nice abilities, like turn undead to power stuff. If nothing else (ie: you are intent on wasting your casting) you can always use the few spells you get for healing, and you can use wands of CLW. But elation is a nice party buff spell and it is a morale bonus to stats and speed, which is somewhat rare.