IE7 predefined language tags contain the following that use script-based distinctions:
az-Cyrl-AZ
az-Latn-AZ
bs-Cyrl-BA
bs-Latn-BA
iu-Latn-CA (no Can. Syllabics script version, surprisingly)
sr-Cyrl-CS
sr-Cyrl-BA
sr-Latn-CS
sr-Latn-BA
uz-Cyrl-UZ
uz-Latn-UZ