Thanks! Good sugestions!
I still wanted to have a slashing lance though =(
The best bet would be the weapon shift spell from the spell compendium. It is a level 1 sorc or level 2 bard spell, which allows you to shift a weapon from one type into another. It works on magic weapons and weapons retain special materials. It is questionable though if it would work with the thunderlance spell. There was a heated debate on wizards 3.5 spell boards about if thunderlance is a spell or a weapon (although that threads focus was on if it bypassed DR and if it really did force damage). I would allow it as a DM, although I don't think it is RAW.
I might suggest the build: Bard 2/Paladin 2/ Cleric 1/Dweomerkeeper 1/Bard 4/Sublime Chord 1/ Dweomerkeeper 9
Praciticed spell caster should cover the 4 non-bard levels for spell casting level. Dweomerkeeper can boost bard by 1 level to get you to 7th level progression for 3rd level spells early, and progress sublime chord afterwards. The dweomerkeeper is a web enhancement for Complete divine, so maybe the DM won't let it in if web stuff is out. The key with the DK is the ability to cast spells without material or xp components by making them supernatural instead of spells. This has the added benefit of making your thunderlance non-dispelable. You need the magic domain from the cleric, but you might also be able to pick up the travel devotion that you were interested in. Also since the races books are in, Races of Destiny has the Illumian race. No HD or LA, but they can get the ability to burn turning attempts to apply a metamagic to a spell for free twice a day. Like divine metamagic, but it does not have to be a divine spell. It will allow you to go the persistent spell route with thunderlance to always have the spell up. You can also select their ability to get a +2 caster level if you want to take more DK levels sooner in place of bard.
Also if you are going with the thunderlance. The spell compendium has come evocation robes that add 2 points of damage to a evocation spell per spell level 3 times a day. The robes cost 10,000gp and will boost your thunderlance damage by 8 points.