As a node operator, different customers want to select different sources of MEV. To enable efficient distribution of validator keys across regions and consensus client types, our validator clients hold keys from different customers.

Teku and Lighthouse support specification of fee_recipient at the validator key level.

It would be great if mev-boost / builder-api could utilize the same file but with an added parameter per validator key to select the appropriate relay when that particular key is chosen to propose a block.

This would also enable solo stakers who have more than one validator to explore different sources of MEV without having to run multiple nodes.