Q208: If a multiclass duskblade has spells from another source, may he use his quick cast class feature on them?
The PHBII text says: Beginning at 5th level, you can cast one spell each day as a swift action, so long as the casting time of the spell is 1 standard action or less.
It seems like there isn't any reason you couldn't, unless I'm missing something. But that also seems kinda wrong.