Yes, I did look at that. From what I could tell, though, it looked like a role would need set up for every customer with every associated user (they'd also need removed as customers' staff turn over). This is fine for a small number of customers, but it doesn't seem like it would be easily maintainable as business grows.
Also, would this need set up on a report-by-report basis? If so, then that compounds the issue of maintenance.
Are there alternatives to managing RLS manually through Power BI desktop? Is role/rule setup available through the SDK?
I'm pretty new to all of this, so let me know if I'm wildly off-base here. I'm also open to utilizing other types of data sources, if there are better solutions. For example, if a report could pass along user info to a REST or OData endpoint, then the data could be filtered server-side before it even makes it to the report itself.