I found a font editor for Pokémon games on the Nintendo DS. It's called PokeFontDS and was made by evco1 in 2008. The program is available for download in the PokéCommunity forum [1].
This utility allows you to edit the font used in Platinum, Diamond & Pearl, HeartGold & SoulSilver or Black & White.
[1]
http://www.pokecommunity.com/showthread.php?t=219606 (In order to download the attachments in the topic you would have to register an account, but that's vBulletin's failure.)
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