Well translating header files from C to Pascal is nothing new ans you can tell from the amount of documentation. Starting on a completely new translation will mean it will take some time before you can actually start to see it's use. This also means if you start such a project, you may be tied to it for a while. Consider that before you start such a project.

It would also help to gather some collaborators to help with the translation, depending on the complexity of the libraries you are supporting.

SFML is new to me so I'll have to check it out myself, though I still find SDL to be quite handy for learning the basics of game programming. What advantages over SDL does SFML bring to the table?