I would imagine that many of Horikawa's advanced students can perform the exercise I detailed as it is not a very high level thing. Come to Japan for some extensive training (develop a relationship) and then pose some aiki challenges for the purpose of exploring pertinent techniques. So long as it applies to a technique you are learning, I can't see why a teacher would turn a request like this down.
Thank you for inviting me to Japan. That is currently not an option for me. However, I've heard there are some people here in the states that can teach such skills as well. I hope to be able to train with them some day. Enjoying your input to the thread, so please continue.