WOW 40! I had a large bridal shower of 40 also! I'm sure you will have so much fun! Well my theme was tropical oasis (hibicus flower was the inspiration of my host). They had flower pots from Target, filled with seeds, hand sanitizer, goodies, cute beach stuff and a hibiscus pen.
Okay, that doesn't really answer your questions but here are some tips:
(1) search the dollar isle at Michael's and Target for some items that may catch your attention.
(2) Surf Oriental Trading they have a lot of luau themed items. VERY Reasonable items, most items are not cheap but if in question read the reviews!
(3) Also use some of the same ideas others are using for the wedding reception such as personalize chapstick, candles and cups.