Why does this matter to you? I got in touch with Jim Gibbons at Dark Horse, who checked in with DH pres Mike Richardson-- they ARE planning to include some manga in DHP, although which titles and what kind of content haven't been finalized as yet.
DHP has offered up manga before-- I can't tell you exactly how much or how often, but I found at least one issue featuring a Dirty Pair preview --so I'm glad to see they'll carry on the tradition; hopefully it'll continue to introduce comics readers to manga (and perhaps vice-versa).
If you want a couple of slightly educated guesses on what manga might appear in DHP-- Kurosagi Corpse Delivery Service, which Dark Horse Entertainment managed to get a movie deal on, seems like a likely bet. CLAMP's works are always a possibility, and Dark Horse has been releasing omnibus editions of their titles. And I'd hope to see the Yoshitaka Amano-illustrated project Shinjuku previewed there as well.
But that's all speculation and wishing, of course! Do any of you guys remember picking up physical copies of Dark Horse Presents? I'm looking forward to 'em myself!