Well, I can scout YouTube and attempt to find some high enough quality videos of the PSP SotN, and rip 'em from there, and run 'em by you to see if they're good enough. Course, YouTube (or almost any video streaming site) is known for lowering quality...
If you can't use those voices in the game, though, I'd be fine with it, even though I do prefer the PSP version voices. Oh yeah, the Dungeon main website has all the cutscene audio with their Japanese versions. All you'd need to do then is rip the Japanese grunts and such to put in-game, and then you can have two language options. I think. I dunno what more would need to be done.