I am aiming into an integrated solution for Proof-of-Stake Ethereum.
I’ve proposed a soft fork to enable miners (and in future stakers/validators) to be relayers (just like they do with regular transactions), see https://github.com/ethereum/EIPs/pull/2473
This changes can be done to geth/others, without a consensus change, and then smart contracts can then always forward gas payment to block.coinbase and stop having to deal with a separate ecosystem for relayers, instead the same gas market gets extended for other tokens.
For the use-case of EIP-2473 become more efficient, I proposed EIP-2474, which allows block.coinbase to make calls, see. https://github.com/ethereum/EIPs/pull/2474
In regards of EIP-2473, it mentions EIP-1077, but we could support multiple standards if needed.
I’ve also updated, and is still WIP into a new EIP-1077 interface which encodes only gas payment stuff, leaving the rest to be evaluated by the wallet/account contract, and considering the gasBase to enable the refund of the gas payment to relayer.