A white-label product or service is a product or service produced by one company (the producer) that other companies (the marketers) rebrand to make it appear as if they had made it. -wikipedia

I'm designing a auto-generated reporting system. This allows our customers to view reports and also download them to send to their clients.

I'd like to make the online version and printed out version as closely the same as possible. The issue is that I'm having a difficult time creating template design for the PDF version to account for customer branding, especially for their logos and additional headings and footers. Some customers want exceedingly long headings (besides organization address, but a list of their board!)

Any ideas or practices that can help lend to a cohesive design for all customers?