I got the seat's at a reasonable price, around £500.00 for the pair if I remember rightly, then I had to make some custom sub-frames as all the pre-made ones available sat too high. I wanted the position just right, it sits low but gives you a good field of view.
As for the discs in the first picture, their from Bill Brockbank @ Badger5, I believe he is still able to get these if not you can have certain machine shops cut grooves into a normal Brembo disc.