For those interested, I took up the challenge and here is what I could come up with:
% makedmg.exe command-line help makedmg - iOS Build Environment's .dmg file creator by Pierre-Marie Baty Usage: makedmg <outfile.dmg> <pathname to app dir> [-v] Example: makedmg myMacApp.dmg C:\Path\To\MyMacApp\BuildOutput To create symlinks, put one-liner files containing just the symlink target. To set a custom DMG icon, put a .VolumeIcon.icns file in the root directory. To set a custom background, icons placement and sizes, place a .DS_Store file in the root directory (you can generate one with macOS and reuse it). Binary Mach-O files and files with a shebang (#!) get execution flags (0755). %
Get it here: https://www.pmbaty.com/iosbuildenv/makedmg.zip
And let me know if you find any issues. Merry Christmas :)