Not per se emulation, but they do involve vintage homebrew. Live stream samples on their site are all kinds of good. Kinda like the Cave Story soundtrack on steroids and blended seamlessly with live instruments \m/,(]^_^[)
I got really excited when they announced that they'd do the soundtrack to the Scott Pilgrim game that was released last summer. Really love their style. There are other great chip tune artists out there, but what I like about Anamanaguchi is that they also use real instruments.
There are also some free tracks on their site, the Summer Singles.