Melvins Classic fords stocks them. Hopefully this link works. http://www.parts123.com/parts123/yb...~S4AS144F2497122222450C~Z5Z5Z5~Z5Z5Z50001018o
There are two different sizes in the early style ... standard and Grabber. The Grabber ones are a bit longer and have a notch to use as a pull, making them side-specific. They use a longer base, too, and could be adapted to a standard door panel by opening up the rear mounting point. The doors have provisions for both. (but being a 70, check to be sure.... not sure if it may be a 71-72 feature) The one shown in the Melvins ad is the standard size. Those also were used in the back seat of some other models ... 70-71 Torino, for sure. I have some OK to good used standard ones here, depending on what color you want. Got some longer LTD pads too, in dark green (easy to dye black), same length as Grabber, but no notch.
Not just Grabbers got the longer arm rest. It was used on the deluxe interior....which ANY Maverick could have.
Melvin's has the Deluxe armrest also in different colors. http://www.parts123.com/parts123/yb...~S4AT1FEWRJ10870115350f~Z5Z5Z5~Z5Z5Z50001018o
Don't limit your search criteria. These shorty units probably got carried over from many older Fords too and I do know for fact that some of the old station wagons had them on all four doors. To be more specific.. I have several multi-model links saved for these standard interior style re-pops and they look to be identical to these Mav/Comet units. Many show being used on 71-73 Mustangs(and many other years if my old memory and google pics can be trusted), and 70/71 Torinos(of which I owned 3).
The deluxe are the same as the 71-73 mustang. Side by side comparison in my thread below http://mmb.maverick.to/threads/71-7...unlimited-vs-mav-comet-deluxe-arm-rest.99458/