Does anyone know who makes a cable or adapter that is wired according to
Apple's specs that forces the external output on LC's and the Powerbook's
160/180 and Duo 230 into a true VGA style output signal? The NEC Adapter does
not do this since their monitors are multisync they just route the signal into
the correct pinout but do not switch the Macs output into VGA mode.

Do I have to make one of these or does someone already have one made-up??

The following is the Apple spec for the LC cpu VGA Cable adapter. I'm assuming
that the Powerbooks/Duos will work with the same adapter(?);


Macintosh LC to VGA
 
The Macintosh LC can supply a 640 x 480, VGA timed signal for use with VGA
monitors by using an adapter cable.  The standard Macintosh LC supports VGA to
16 colors, and with the optional 512K VRAM SIMM, the VGA monitor is supported
to 256 colors.
 
Note:     The Macintosh LC supplies signals capable of driving TTL level
          inputs.  However, some low impedance input VGA monitors do not work
          with the Macintosh LC.
 
To connect a Macintosh LC to a VGA monitor, you need to make an adapter cable
from the Macintosh LC video connector to the VGA monitor.  Following is the
pinout description for the adapter cable:
 
Macintosh LC        VGA
Video Connector     Pin     Signal Name
---------------     ----    -----------
1                   6       Red ground
2                   1       Red video signal
5                   2       Green video signal
6                   7       Green ground
9                   3       Blue video signal
13                  8       Blue ground
15                  13      /HSYNC
12                  14      /VSYNC
14                  10      HSYNC ground
7,10                nc      SENSE1 & SENSE2 tied together
 
VGA monitors are identified by shorting pin 7 to pin 10 on the Macintosh LC
video connector.  The Macintosh LC grounds pin 7 on its video connector, which
results in pulling down pin 10 and gives the correct monitor ID for a VGA
monitor.