In an unfortunate turn of events, it was revealed by Siliconera that XSEED is now unable to publish Grand Knights History due to not having enough development resources for localization.
Possible reasons may include the fact that Vanillaware (the developer of Grand Knight's History) could be putting all of their effort into developing Dragon's Crown, of which Atlus recently took over publishing duties (and partial development as well).
In addition, XSEED might have its hands full with upcoming releases, such as the highly anticipated RPG The Last Story, which is set to release sometime over the summer.
Whatever the reason, it's a shame to hear that what could have been one of the last great PSP titles won't make it over here now. We can only hope another publisher will pick it up now, unless XSEED plans to release it sometime further down the road.