Funny thing was as I was typing that I was smiling at a coincidence -- Stan Pranin had just reposted an interview with Katsuyuki Kondo on the aikido journal facebook page. In that interview Kondo also mentioned Kotaro Yoshida as one his early teachers of Daito Ryu. Yoshida certainly had one heck of a reputation and I think we would probably be having very different conversations today about aiki if Aikido hadn't taken off as a "mainstream" art.
Hidden in plain sight... Hmmm, maybe not all that hidden after all...
Daito ryu? I don't think so. I don't have time to look it up, but if memory serves, I think all he got from Yoshida was some form of single sheet makimono on iron fan...and that after a relatively short study period.