If you're CASS try Aloha Air Cargo... I jumpseated on them recently and the whole forward lower cargo bay was wide open for my rollerboard, flight case and a backback I had.... I assume they'd allow a surfboard in there as well?
Dan, I was under the impression that HAL charged $25 for surfboards? (thought that a few guys I know brought boards from HNL to LIH and I know they wouldn't have paid $100) Not doubting you, I did think it was cheaper though?