I'm trying to do both flags and shields. I've already done:
+ Aceh (Indonesia)
+ Basques (Spain)
+ Palestine (Israel)
+ Tamils (Sri Lanka)
+ Kurds (Turkey, Iraq, Iran)
+ Uyghurs (China)
+ Nagas (India)
+ South Sudan (Sudan)
+ Nagorno-Karabakh (Azerbaijan)
+ Trans-dniestria (Moldova)
+ Abkhazia (Georgia)
+ Chechnya (Russia)
+ Somaliland (Somalia)
+ Tibet (China)
+ Montenegro (Yugoslavia)
+ Scotland,
+ Wales - probably creatable through events
+ Assam (India)
+ Catalunia (Spain) - strong national separatist tendencies
+ Inner Mongolia/Nei Mongol (China)
+ Baluchistan (Pakistan) - see Khazaristan
+ Euskadia
+ Kashmir (hindu)
+ Kashmir (muslim)
+ Chechnya
+ Kaliningrad
+ Palestine
+ Kurdistan
+ Quebec
+ Kosovo
+ Taiwan
+ Tibet
+ Ulster (Northern Ireland)
+ Montenegro
+ Corsica
+ Siberia
+ Southern Italy (no name yet)
+ Confederate States of America
+ Wales
+ Scotland
+ California
+ Sicily
+ Texas
+ Hawaii
+ Alaska
+ Puerto Rico
+ Natal
+ Orange free state
+ Louisiana
+ Thrace
+ Trebizond (pontus)
+ Deseret
+ Arizona/New Mexico Alliance
+ Government Loyalist Alliance
+ Northwestern Alliance
+ Chicago
+ Greater Wisconsin
+ Vojvodina (rep.)
+ Flandres
Several lack decent flags, though. They are Chicago, South Sudan, Nagorno-Karabakh, Aceh. Also, I haven't found anything on Karens yet. The extended revolter list I am still working upon. BTW, you make great flags - I've taken some you made earlier (Alaska, Cali and basques,I think), if you don't mind, of course.