There are literally thousands of threads asking for a closed back alternative to the top open backs. If it existed, we would have found it years ago. A closed back with large soundstage and flat frequency response and all the other characteristics of top of the line open backs simply is a unicorn and will probably remain a unicorn until somebody invests some serious R&D money into the subject.
And please slap anybody who recommends Ether C or LCD-XC. Not even remotely comparable. A TH-900 without the V shaped tonality would have been the closest match, but the Fostex line of closed back dynamics are not really closed back, as they are both barely more isolating than open backs and leak as much sound as open backs.