[dd74]

Just came back from a week in K'auai. It is mind-numbing how beautiful it is there.

I'd look into a timeshare before renting a beach house. With a beach house, you're at the mercy of the beach house owner's discretion as to what he/she believes the rent should be. With a timeshare, you can reserve your space, or trade for other spaces.
The best part is virtually anywhere in Hawaii is a key destination for vacationers, so trading for any other vacation spot in the world should be fairly easy.