Good job, looks good.
I put these lines in .emulationstation/es_systems.cfg to launch opk:
*** caution do not try it at home. You gcw0 can freeze
<fullname>Dingoo linux OPK</fullname>
Some applications do not work
Emulation station does not read [Desktop Entry] Categories, Icon, Exec ... attributes
We need a copy/paste of code gmenu2x to emulationstation if you want to run OPK. A little work here.
I'm trying to put a theme to check the memory consumption of ES vs gmenus2x.
Beers for all!