Nomadic Nomads
This simple mod makes steppe nomads immune to "regionless" attrition.
Nomads by their nature are able to live and thrive without static cities, and migrate to new lands without retaining their homelands. This mod allows the player to retain his/her armies without having them bleed away from desertion attrition. They will still desert if you can’t maintain their upkeep costs; however, base income alone can be enough to field a stack or two.
This mod only applies to steppe nomad factions, but can be very easily modded to apply to any other faction.
This mod is simple, nonintrusive, and should be compatible with any other mods.