Multiple Language and Localization settings per institution (was Multiple timezones per institution)

Per the WOLFcon discussion about single-tenant consortia implementations, we are not going to be able to get away with a single timezone per tenant. Multiple timezones are needed, not only for consortia, but also for institutions like Duke who have campuses in multiple timezones (Raleigh and China)

NOTE: So far all the institutions I have spoken with including Duke and the 5 Colleges, have wanted to have shared circulation meaning a single set of users, loan rules and policies and inventory across all campuses (in Duke's case) and institutions (for the 5 colleges). Loan rules and policies will differ depending upon the location, but that's already built in.

I need some help understanding what our options are for timezones. The need to specify a tenant-level timezone (UIORG-55) was actually surfaced by the developers as it was required for logical consistency when calculating due dates, overdue etc. Could the developers provide an option or two for this which I could run by the SMEs for acceptance? Maybe simply supporting user-based timezone for display in addition to tenant-level timezone for calculations would suffice?