It varies quite a bit depending on the type of SaaS business. For sake of answering this with something specific, I'll assume that this is going to work like some of the enterprise reseller/referral agreements I have seen. Since this is new for your business, when writing your reseller agreement, consider leaving specifics of the standards you plan to hold them to out of the contract, but mention that they might, or will, be communicated. In the termination section, give yourself termination for convenience with a short period of notice. This gives you complete flexibility in terminating the agreement without trying to guess before you start signing partners what the issues are going to be. I hope this helps, but let me know if I missed the mark or you want to talk more.

I would probably structure it so that there is a Master Services Agreement with the general terms of your relationship which reference subsequently attached Service Orders (or Scope of Work) each time you engage with them for project or service. When a customer signs up for the SaaS product, I would incorporate SaaS-specific policies by referencing them in the corresponding Service Order.