The CA Legacy is the closest but is noticeable less loud. Also pretty close for tone and quite loud is a RainSong CH-WS, but it is an unconventional 12 fret short scale cutaway compared to an HD-28. Next would be a RainSong H-DR. There are some good YouTube videos comparing this model to various D-28s and I think all of them confirm that the H-DR is brighter. The 12 fret version can be custom ordered and generally 12 fret RainSongs are much closer to the darker tone of a wood guitar. Next even brighter would be a RainSong CO-DR which I used to own and A-B'ed against various Martin OMs and 000s and concluded it was very similar in tone to a smaller Martin, but louder. Here are my comparison videos of old (apologies in advance):
https://drive.google.com/file/d/0B_D...ew?usp=sharing
https://drive.google.com/file/d/0B_D...ew?usp=sharing
I've not got any experience with recent Emeralds. The MacPherson Sable was designed by the same person as all the CAs and might be also worth checking out.