Well, if you wanted something that looked like FF7/8, I dont think RPGMaker would be the way to go, being since...well...a lack of a third dimension x_x
Your best bet is probally the PS2 RPGMaker (no relation) like Halkun said. To my knowledge though, I dont think you'll be able to create something like FF7/8, and I heard the options were somewhat limited, though its better than nothing...
...though I have heard some good things about the 3D Gamemaker from a few friends. I've never used it myself, but I guess it's worked for some people.
http://t3dgm.thegamecreators.com/