One or two comments
1. Wally Jay's Small Circle Ju-jitsu is not Aikido, neither is Aikido Small Circle Ju-Jitsu. This does not mean there are no similarities, after all the human wrist can only bend so many different ways.
2. Cross training in other arts may or may not be necessary or even desirable. However, beware of Aikidoka who have trained in other arts and insist on including their former art's techniques in Aikido and calling it Aikido. I am certain there are folk out there who will attempt to justify using handguns as long as they shoot "from their one point". Just because someone says it is so, does not mean it is.
3. I am constantly amazed at how versatile O'Sensei must have been. If I were to compile all of the alleged things he was supposed to have trained in as mentioned in the above posts, O'Sensei must have never slept. Come on, a goodly portion of his history is known, so please stick with that, not some daydream conjured up to justify a point.
4. Lastly, the whole discussion of what O'Sensei did as a young man begs the question and ignores what he became. At a very specific point in his life he changed from doing Daito Ryu Ju-jitsu and began his path in Aikido. We have many statements from him where he identifies himself with Aikido, none where he does the same for anything else. He changed and transformed himself and his art into something that had not been seen previously. The lotus is not admired for its' roots in the mud, but for its' flower.