Update: Officially announced. More details available here.
Siliconera can reveal that Aksys Games are publishing Muramasa: The Demon Blade for PlayStation Vita in North America.
In Japan, the PlayStation Vita version of Muramasa: The Demon Blade is being published by Marvelous AQL. You can watch a trailer for it here.
Downloadable content with four new characters will be made available for Muramasa on Vita following release in Japan.