It's also said to be using a modified version of their Street Fighter X Tekken engine. This same source spilled on Resident Evil 6 featuring Chris Redfield and Leon S. Kennedy.
It would seem this insider knows what they're talking about and isn't just guessing. "same inside source" now blabbing about Darkstalkers 4.reports it's this
The Capcom brawler "has been in the works since last year, with Street Fighter IV and Street Fighter X Tekken producer Yoshinori Ono at the helm. The unannounced fighter would use a modified version of the SF X Tekken engine, which itself is modified off of the Street Fighter IV engine. Principal development on SF X Tekken was said to be complete towards the end of 2011, which is when Ono supposedly shifted his attention to Darkstalkers," they write.
"We have made no announcements," responds Capcom to the subject of Darkstalkers 4.
The last major instalment in the series was 1997's Darkstalkers 3. Notable characters from the series have since had cameo appearances in other properties like Marvel vs. Capcom 3. Will this year's Captivate event from Capcom include some Darkstalker goodness? Rome is tipped as the host for 2012. There's also E3 and TGS, of course.