Had some time to do roundabout custom collections for emulationstation. This is way more work than the implemented method in up to date ES versions on other systems, but to me its worth it. I used the gbz35 dark theme I posted the other day and tweaked the graphics for the auto-favorites "system" to use for my collections
Take final fantasy as an example for this. There are games in this series that can be played on nes, snes, gba, and psx. I like to put them all in one collection, but the es_systems.cfg does not allow for different emulators to run different filetypes from one "system" folder. So I created scripts to launch each rom (make sure they are executable), for example, final fantasy iii.sh, which contains the following:
opkrun /media/sdcard/emulators/pocketsnes.opk "/media/sdcard/roms/super nintendo/Final Fantasy III (USA) (Rev 1).sfc"
or final fantasy vii.sh, which contains the following
opkrun /media/sdcard/emulators/pcsx4all.opk "/media/sdcard/roms/sony playstation/Final Fantasy VII.pbp"
After creating scripts for each rom, I made a folder on my external SD called scripts, then a subfolder for each collection, final fantasy in this case (also did rpgs and zelda thus far).
In my es_systems.cfg, I added auto-favorites as follows
I then started emulationstation and tested each rom, took the gamelist.xml file it auto creates, and linked the images to the pre existing files like so.
<path>./Final Fantasy/Final Fantasy 7.sh</path>
<name>Final Fantasy 7</name>
<image>/media/sdcard/roms/Sony playstation/boxart/Final Fantasy VII.png</image>
I also added a boxart folder to the scripts folder and added images for the subfolders. These get added to the game list.xml as follows:
All said and done it looks great, but I definitely don't recommend it unless you have alot of time to kill.