1.6 ships with XFree86 4.2.x. In order to use it on macppc you 
need a Rage 128 or later video card. It needs a VGA ROM in order to 
soft-boot the card and get modes from. None of the onboard ATI chips have 
any such support. The only thing you could do is manually hack something 
together or go back to X11R6.3 and use X in 8 bit color. Someone correct 
me if I'm saying the wrong stuff.