Xconfigurator knows that my ATI Mach64 Rage IIc card can do
1600x1200x16bit, but doesn't provide a working modeline for
this res. When it tries to start up, it complains with "Bios
says this mode is illegal." Unfortunately, all of the
provided modelines seem to require too high of a dot clock
for this cheap piece of crap video card that I have.
Fortunately, I hacked out a modeline that'll work:

Modeline "1600x1200"  159    1600 1601 1695 2012  1200 1203
1206 1240

There should, obviously, be no carriage return in there,
though this textarea box that I'm typing in might've stuck
one in there. My monitor, a MAG Innovision XJ810, claims
that this modeline generates a V refresh of 63.8Hz and an H
refresh of 79.1kHz, which is not phenomenal, but it's close
enough for government work. I imagine some playing with
Xvidtune might get something better, but this is, at least,
a starting point.

Thanks,
Max