Hey Dave,
The D0ZZ-3649-A emblem appears to be a Scott Drake product, making it a single source part for all vendors. It explains why everyone seems to be out of this part at the same time. I saw one site with "Estimated to ship direct from the manufacturer on 10/02/23, pending manufacturer availability". It gives new meaning to waiting on a slow boat from China!
I checked all my typical go-to sources and found the same as you. I will suggest a site I've used extensively (before I was aware of OMS (Ohio Mustang Supply) and NPD. Virginia Classic Mustang. I used them for several Mustang restorations on a few of the boss' stable of toys. The last two were a 65 K code coupe and a '67 Mustang GT fastback, and they did a great job of shipping what I needed for them. They show the D0ZZ center on their site, but I don't know if their inventory updates in real-time. I did not see any out-of-stock or back-ordered notices indicated. I suggest contacting them to make sure they have one. Their number and hours are at the bottom of the link page. As mentioned earlier, this piece is a single source part, and with everyone else out of stock.....it's worth a call.
https://www.virginiaclassicmustang.com/70-3-SPOKE-STEERING-WHEEL-EMBLEM-ONLY-P3282.aspx
If you don't find the D0ZZ emblem at the above link or any other sources, ib4stang's suggestion is a viable idea. The '69 emblem does attach differently to the wheel center. The three tabs are used to attach the 3649 emblem to the 3D752 trim cover, which is then attached to the 3623 pad. On the '70/ version, the emblem friction fits directly into the 3623 pad. At one time, I had a 3-spoke wheel from a '69 Cyclone and some emblems from a '72 Gran Torino (which uses the same wheel and pad as the 70/ Mustang) that I could have checked the measurements between the different emblems. The "had" unfortunately means I gave them away after tiring of them always being in the way, so I have no way to measure if there is any diameter difference. With the tabs removed from the '69 version, they might be the same size. At least at a lower price than the D0ZZ-3649-A emblem; if it doesn't fit, it won't hurt as much when you put it in the junk drawer.
The illustration below is the '69 3 spoke wheel detail; the second is the '70/ version, and the third and fourth are the reverse side of the '69 emblem and the '70/, which in this case is the Torino wreath style, but still the same emblem housing.
