Usually rubber isolators are used to prevent transmitting noise or vibrations. I've not seen them used between a TT body and frame. Since a person is not allowed to travel in a trailer while it is moving on the road, road noise is not an issue nor have I heard of any vibration problems except those caused by unbalanced wheels.
It would be of interest to know the rationale behind the concept. If you find out, please keep us informed. We are an information hungry group and many are willing to try new, interesting ideas.
Thanks for exposing us to an interesting topic, Josh.
Kurt & Ann K.