Are there any mods available that would make Arena and/or Daggerfall playable with a PS3 controller? I know the mods exist for Morrowind, Oblivion and Skyrim. I don't even know if such a mod is even possible as these earlier games were based, respectively, on DOS and MS-DOS.

Xpadder will work with any controller, including a PS3 controller. You just need a driver to make your PS3 controller connect to your PC.

Thanks for the info.!