I know this is an old thread still:
If you search Pranin's Aikido Journal and read interviews with Tohei & Inoue, you will know Kushida started with Inoue, the senior most student of Shioda. And Kushida was Gozo's uchi deshi for the longest time. So if "uchi_deshi"'s teacher taught Kushida, he must be Gozo Shioda himself. Not bad for a guy who is dead for 16 years!
I think Kushida broke off after they installed Gozo's son, who was much junior to Inoue & Kushida as Kancho (same thing happened with with Aikikai and Koichi Tohei).