I think that Nalia would be a good option for a romance. Especially for a male Paladin or Cleric character...based upon all of her "help the needy" whining. That might appeal to a "godly"-type PC. It could also put an interesting spin on the Fighter Stronghold if placed into BG2 as part of the "add-in" of ToB.
For the gals, I've got to go with a romance script for Minsc. That would be absolutely hilarious! I can't even imagine what he'd want to do with that hamster.
Maybe the designers limit this romance script to a female spellcaster so that he adopts them as his "witch". Just my 2 cents...
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The only good giant is a dead giant!
---Throntar the Battlerager---