Simple answer, there aren't any PSP translations since they seem to be hard to do. Hell I've only heard of 2 games that have been semi/translated before a US release and that was Monster Hunter 2G Portable and Final Fantasy VII Crisis Core.
Popcorn Fairy said:
When something like Fate/Unlimited Codes gets localized, there's really no need, as anything worthwhile will be localized anyway.
Fate Unlimited Codes thats 1 that maybe got localized, but I can clearly say there's plenty that should be localized but aren't going to be.
Just to list a few,
Bleach (both Heat of the Soul and Soul Carnival series)
Clannad
Gundam (Series)
Hatsune Miku Project Diva
Initial Stage D: Street Stage
Kanon
Kateikyoushi Hitman Reborn Battle Arena
Macross Ultimate Frontier
Tales of the World Radiant Mythology 2
There's probably a lot more that aren't going to get localized.