I have Canna 'Tropical White' purchased at a Home Depot. Very close to white but the petals are very thin. Like a lot of other white flowers they don't hold up well if the flowers get wet.
Check out this site
Karchesky and Harris Canna Collection
They show many white Canna cultivars. They are located in Australia, it would be challenging to have them sent to California. But you can see the different flowers and names that you can search for.