I have never heard anyone else say they are allergic to bananas. Are you allergic to avacados? These allergies are related to latex allergies. You may not be deathly allergic, but chances are you have some form of the allergy. Sorry to ramble on.
I used to use silken tofu, until I got off soy. It is magical. Has no flavor. Silken tofu is sold in the aseptic boxes on the shelf. It makes a truly thick milkshake or smoothie.