I saw them on ebay, and I personally won't buy them because they seem to have defects (on the right side of the earpad on the right of the photo). But as I didn't test them, I may be wrong.
If you decide to buy these, tell us what you think about them.
I have one pair of CD3000 with genuine Sony earpads in rather good shape, while the others (several CD3000, one CD1000, two CD950, one CD750) are equipped with recent replacement earpads : the genuine earpads are very comfortable and soft, whereas the replacement ones are firmer (but still wearable for hours) and thicker, and I think this thickness slightly improves the deepness of bass and the realism of sound (realism : especially in the case of the CD3000, of course).
Regarding making earpads in real leather, I tried last year to find someone able to make genuine lethear earpads, but the person I asked for told me they were very difficult to make. So at the present time I keep on using the replacement earpads, and I must admit they are quite good, even if you can't forget you're wearing headphones, as it seems to be the case with a Sony R10, according to Modwright01.
Anyway, if someone finds a person able to make good quality and comfortable real leather earpads, I may be interested.