No offense but if you can't find one of those cases on eB or AExp you are doing something wrong. They are literally a dime a dozen. The small soft ones are handy if you're throwing your phones in a jacket pocket or something safe for sure though. But my zipper pull broke off after just a couple weeks of use so I trashed the IMR case.
If you go back a few posts you'll see a bunch of folks who use the crushproof/waterproof Pelican 1010 cases for over the top protection. A 1010 fits my DAP & R1 perfectly and I don't have to worry about throwing it in my work bag next to my coffee tumbler. I know you said the "same" one though. Just something to consider. The 1040 fits my DAP, phones, amp and extra cables, filters and tips