Thanks to a member named Louis, I have confirmed what I had already suspected.
It appears some countries have a different, or I should say, have two font encodings. Specifically the mainland Chinese version PS2 has a font with full Simplified, and Complex Chinese character support. It appears to use the Big5 encoding.
I would also guess that the Korean PS2 has another font for displaying Korean, as I have not seen support for that in the default font set.
If anyone else has found other region PS2s that have support for another font encoding, please let us know.
For starters I'd like to know if any PS2's have support for any script based languages such as Arabic, or Thai.
I might start another thread, or change the name of this one if I can compile more non-SJIS font related stuff.