Hello, sorry for late reply. TaoEffect is not aware of any tools which cold mount the disk images on other operating systems. Note that there is a difference between dmg disk image and sparsebulde disk image, as the later is in fact a folder where the data is spread across small files called stripes or bands, so it is a bit particular.
All I can do is search the web, which you did already....
An ISO image is possible to create with disk utility and will be readable on Windows and Linux, but AFAIK this one cannot be encrypted, neither can Espionage use it.
Rgds
Zsolt