I was just joking when I wrote "famous hairy Opuntia", because just the opposite is the case. This plant does not seem to be known by many people. To the forum members however, it is well known, ever since I posted an image of it on cactiguide in order to have it identified. That was in 2005 or around that time. Also, I do not know of anyone that has ever seen this plant in flower. As a matter of fact, the opuntioid expert Dave Ferguson does not know, what parent plants were used to create this hybrid.
I had shipped a cladode to him in 2007 and it has yet to bloom, but it is still growing. So your question about the mature plant cannot be answered by me. The cladodes of this plant are elongate elliptical and do produce the same hairy areoles as the older stem sections. For lack of a better name I did choose the term "Pony Tail Opuntia". It is not present in Google, because it is not acceptable and/or established as a common name.
There is no known source or supplier. All I know is, that these pads are brought from Mexico. The grower (hybridizer) is unknown.
This plant is definitely a cactus that falls into the Opuntia genus. Mr. Ferguson doubts, however, that it could be a hybrid produced by cross breeding an Austrocylidropuntia and a real Opuntia, because they are very distantly related and thus most likely incompatible. He told me today, that he cannot get distantly related species with flat joints to hybridize.
I had hoped, that someone from Mexico would come forward and give us some more information about this unusual prickly pear cactus member.