I know I saw a bag containing at least 100 smaller bands that can be used to create the completely braided hairstyles in the drug store's hair accessory section but can't remember if they were made by Goody or Scunci.
I also used to braid my horse's mane and got bags of 500 tiny rubber elastics but the horse didn't mind having his hair pulled! Those can be found in tack shops.
Good luck with your quest!