Besides Yudkowsky and Goertzel, the only person I know of doing serious computational meta-ethics is Dutch philosopher and computer scientist Gert-Jan Lokhorst. He has a paper forthcoming in Minds and Machines called "Computational Meta-Ethics: Towards the Meta-Ethical Robot." I suspect it wil be of interest to some.
His paper also mentions some work in formal epistemology on computational metaphysics and computational meta-modal logic. Ah, the pleasures of scholarship! (You're all tired of me harping on about scholarship, right?)
Maybe I'm missing something, but I'm not too impressed by this. It seems like exactly the sort of thing that Eliezer was talking about in "Against Modal Logics" — putting all our confusion into irreducible modal operators and using deductive reasoning to move those boxes of confusion around, instead of actually reducing any of the things we're trying to talk about. What metaethical claims are even being made in this paper, other than the rather obvious desiderata on page 5?
It's not making meta-ethical claims. It's presenting a system for how you could implement meta-ethics in a machine agent.