Rehearsal dinner for 100 santa monica/venice or westside
Number-wise, it's entirely possible. Price-wise, I'm not so sure, especially for the area you're looking. The best option is to rent out an entire Chinese restaurant in SGV, like Mission 261, Ocean Star, or NBC Seafood.
You could call around some places on the westside. I think hotel dining rooms may be your best option, like JerNe in Marina Del Rey, Ocean and Vine, One Pico at Shutters, or Whist at the Viceroy.
Perhaps also calling around some of the restaurants lining Ocean Ave., like ICugini, Il Forniao? They 'might' be willing to close down the restaurant for you on a not so busy night, like a Monday.