RPG maker 2K may be able to be ported although it has no public SC, however it would take ages of tempormental researching.
I did have it installed at one point on my system, and it saves your maps as files, and the overall game as a file too (I think) the RPG Engine EXE just reads the game file and interprits the In order to make the files playable on the GP32, you would have to spend ages information that is held there.using proggys such as Hiew and hex editors to look through the files and figure out how it saves, and how the EXE engine interprits it (what parts of the file store what and how it displays it on the screen), As I no longer have it installed on my PC I don't know if it saves as readable in notepad strings, this is very unlikely, but if it does it will probably be easy to understand. But my bet is it uses some arse burningly long file header that will take ages to understand,
I think a port is about as likely as me relecing anything for the GP this side of the year. (close to impossible)
But if anyone does decide to go for it then good luck too them.