Clockwork, I'm sure others will disagree with me but I always thought the look of 225/50-15 and 285/50-15 P7's on 8" & 10" Campy's was perfect for a stock bodied Pantera and the "stance" with that combo was great. As a 225/50-15 is only 23.85" tall, finding a 17" tire with a similar diameter is pretty tough, keeping in mind that you need to find a rear tire that matches.
Most owners wind up going taller on the front and shorter on the back, than the late OEM P7's. A 235/40-17 is about 24.4" tall and a 245/40-17 is about 24.7" tall. Some Vendors recommend a 225/45-17 on the front but since it's even taller than a 235/40 or 245/40, I can't imagine why. A 335/35-17 is about 26" tall and a 315/35-17 a bit shorter. My recommendation would be a 235/40-17 up front and a 335/35-17 (or 335/30-18) in the rear. You could go to a 335/30-19 (Nitto NT05 - 26.89" diameter - great dry tire) at the rear but you run the risk of not being able to buy new tires at some point in the future, because it's an unusual size.
If you want to go bigger, like 18" front and 20" rear, that's fine but be careful going too tall on the front. A 235/35-18 is 24.5" tall and a 245/35-18 is 24.8" tall. If you went with one of those sizes up front, you'd likely pair it with a 325/25-20 at the rear. Keep in mind, with a good spring/shock package, the "stance" of the car no longer depends upon tire diameters.