There isn’t, really. Some people have modded 7506s as they’re relatively easy to take apart, but you’d need some know-how.
I think that’s why the M40X has become so popular in some circles. It’s the next closest thing, and it works with the short cables people sell for the M50X. I think the Sony pair is much more comfy and I prefer the sound.
Alternatively, check out the Pioneer HRM5. Not as bright as the 7506, but a very nice, balanced headphone with a removable cable.