This is why it works: Playstation: 33MHz. PPC: 400MHz. Although that is not going to be even close to translating directly, it still means that the PPC can do 400 Million somethings per second, while the Playstation can do only 33 Million (x2? x4?) somethings per second. A ton of the somethings on the Pocket PC are wasted doing emulation steps (i.e. translating Playstation doings to Pocket PC doings), but still. And the Pocket PC can do 3d rendering, albeit not too fast. I mean, you've got both Quake1 and Quake 2. Granted, Quake2 isn't really playable, but you do have a commercial version of Tomb Raider, which was once a Playstation game (although it still is a little choppy).
You don't need to have 3d hardware in order to do 3d graphics, obviously. It all has to do with how much qualityyou want in your 3d graphics and how fast you want to do it. Luckily for this project, Playstation has pretty horrible 3d quality. I mean, no texture filtering... Heck I don't even think the Playstation has perspective-correct textures! Either way, those are things you get to play around with in order to get your game playable.