There are very interesting substitution levels (Mystic Fire Knight) for a Paladin of Mystra in Champions of Valor. One nice thing you can do with these is head for Suel Arcanamach at 7th level, using only Paladin levels to qualify. This nets you great Charisma synergy, the ability to make dispelling strikes, and a quick spellcasting progression using Sor/Wiz spells of certain schools, taking you up to 5th level spells. Nice gish lite you can make that way.
Surreal had a build which could really abuse caster level shenanigans to get a Paladin caster level of 30 or so on top of full Suel Arcanamach casting. This is it:
Mystic Fire Knight Paladin 6/Suel 4/Abjurant Champion 5/Sacred Exorcist 4/Something 1
Where Sacred Exorcist and Something all go into paladin casting. The jist of it is that Abjurant Champion sets your Suel CL = BAB, which should be about 18. This then stacks onto your paladin casting, which puts it at around 28 (and you have 3rd level paladin spells).
You can also do this without the 4th Mystic Fire Knight sub level, so you get Turn Undead much earlier - which in turn fuels Divine Feats (Divine Might?) and Devotion Feats. If your game doesn't go all the way up to 16th level or so, you're probably better off going straight Paladin at 4th and get Divine Might and stuff ASAP.
In this case, I'd recommend Paladin 6 (MFK sublevels at 5th & 6th; Charging Smite variant)/Suel Arcanamach 4/Abjurant Champion 5/Spellsword 1/Dragon Disciple 4. Your abilities should go like this: Cha>Str>Con>Int>Wis>Dex. Cha fuels your saves, smiting, Suel spellcasting, turning attempts. Str and Con are obvious for a melee guy. You need a few skillpoints, especially if you're not Human, so Int 12 is a good way to go. Wis should be at least 11, maybe 12 for one or two 1st level Pally spells (i.e. Rhino's Rush). Dex can be dumped entirely, you'll be wearing heavy armor much of the time (Mithral Full Plate is no problem later on).[FONT="][/FONT]
