UPDATE TIME:I got my replacement board set for the D9200 on Friday, and swapped out the main board (I decided not to replace the neck board, the VGA connector board, or the little control pad).
The swap was moderately easy, with only one misplaced cable (the degaussing control cable), which the WG tech support helped me catch.
Bottom line? It Works! Even Better Bottom Line? It Works Better!

Seriously, the picture is much sharper in VGA mode than it was before. In fact, everything onscreen looks better than with the original board.
I'll be updating my D9200 review with my new findings.
Oh, and about the whole 800x600 controversy -- I did discover when I first connected up the monitor that it gave me a "Signal Out of Range" message onscreen, as I hadn't changed my monitor settings in Windows. It seems that, like most modern multisync monitors, that the D9200 has some signal protection built in.
That leads me to suspect that even though 800x600 isn't officially supported, that it may be within an acceptable signal range.
Kevin