One such project is RWKV[1]. On the open source leaderboard it lived in the middle of the board for a while, so it really is a legit approach, it's just not hot.
What's really needed is a leaderboard based on some private test sets, where you can submit a model to be judged and some entity will run it on their own machines without disclosing the tests to you. Even that could be vulnerable to cheating if the submission process is automated and you can submit many times, as you could use the score as feedback to disclose information about the contents of the private test set. So it would take some care to run such a service, even beyond normal security concerns like securing the sandbox that submitted code runs in, etc.