needmoartoys
New Head-Fier
I wondered the same thing, about the only options I found are T50rp mods like the argons or the newly open-source alpha dog: https://www.head-fi.org/threads/open-alpha-t50-3d-printed-headphone-project-from-mrspeakers.825868/there are any other planar closed back like the Monolith M10600C, or is it the cheapest option?
If you get the T50 cheap, and you have a way to 3d print cheaply, there's a chance you could do one of these overhauls cheaper than an M1060c.
If you are willing to compromise on the planar magnetic technology, the DT770 pro delivers super strong bass performance out of the box, and super clean mids IIRC. Some tuning foam or paper towel should be able to cut down on the harshness and graininess the beyers have, although I haven't heard it modded. A used 770 will cost you a good $100 less than an M1060c, and doesn't need a headband mod.