Thank you all for your suggestions.
We have looked at ESPCs. They fall under a different authority, but we have talked to people using them to learn about their best practices. I am very familiar with FPDS. However, the data in the check box is not reliable. I am not sure what people are using the check box for, but they aren't actual multi-years. We have actually found other long term service contracts (under working capital funds, utilities, the ESPCs mentioned above) and talked to the offices managing them, but they are not using the multi-year authority. It has been a surprise to us that the multi-year option appears to be so seldom used for service contracts. Posting here was a bit of a hail mary.
We will definitely check out the chemical demilitarization program, it certainly seems to be a good candidate. Thank you Joel Hoffman.