Gathering for Memorial
I forget how many the back room at Cafe Bizou holds... might be worth calling and asking, assuming you're looking for food as well?
If you want somewhere less pricey, there's the banquet room at Barone's that holds up to 90...
Spazio in Sherman Oaks
The 94th Aero Squadron in Van Nuys
Castaway in Burbank
Olivia in Burbank