Pacific Princess, Celebrity Solstice and Royal Caribbean's Radiance of the Seas all do one way Vancouver to Honolulu. Carnival might have one too. You won't find one from LA. Rhapsody of the Seas might also have one but I know they're moving her to Europe I just can't remember when.
Not recommending them as an Agent, but Vacations to Go has one of the best cruise search engines out there.