Olive grows so fast, you can get a descent tree from Lowe's and chop. You will have a workable stock next year. For you, I'll try to post an update pic on 2 of my Lowe's olive this weekend. Both were purchased just a few months back.
When you mean source are you referring to information or actually purchasing one? I don't know if you would be interested in this. However, as of a couple weeks ago, New England Bonsai had a pretty powerful specimen for sale. It looks like the only thing that was done, was to give some very basic structure to the branches. If I remember correctly, it has about a 5 inch base and is only maybe 11 inches tall. A very old looking tree.
I don't think it is on their site. However, if you email or call, you can probably get a picture and some info on it.