I would like to think I was making good progress on this issue when I starting running into probems and found this thread. Let me explain what I've already tried:

Situation:
Virtual PC 5.2 running on Windows 2000 SP4
Guest OS is RedHat 9
VPC properties tell me 8 MB VRAM, and I configured 128 MB main RAM.

Goal:
Getting X to run at 1152x864 at 16-bit color.

I am already somewhat familiar with the XF86Config file, and with some help from google and this forum, I have accomplished the following:

1. I can boot into 1024x768 at 16-bit color
2. I can boot into 1152x864 at 8-bit color

If I remove other modes from the file to force 1152x864 mode when it is configured for 16-bit color, I get errors when X tries to start. I could include my XFree86.0.log info if it would help.

Things I have already tried in XF86Config:

1. Tweaked the values for HorizSync and VertRefresh
2. Tried both Trio64 and Trio32
3. Tried both 4096 (default) and 8192 VideoRam
4. Tweaked the DefaultDepth, Depth, and Modes lines

Has anyone ever attempted / succeeded to configure X running under Virtual PC to run higher than 1024x768 with 16-bit color or higher?

TIA,
harry349

P.S. I posted this question as a reply to an old post in the newbie forum but didn't get any response, I didn't really think this belonged in the newbie forum in the first place, so I thought I'd try here...

Well, after installing WinXP in Virtual PC, I notice very similar behavior - I cannot change my video mode to above 1024x768 unless I bump my color mode down to 8-bit. Unless someone has some additional insight here, I guess I'll have to take this as a limitation of Virtual PC.