What this is about
The question behind the question is actually how to place four virtual machines with 800x600 resolution on a screen smaller than 1600x1200. I am trying to enable split screen Battlefield 2 gaming on my gaming laptop (yes, with four keyboards and four mice), and few projectors support a resolution high enough to show them all without some kind of downscaling. The laptop runs Windows 7 Home Premium x64 and has an Optimus setup with Nvidia GT 555M and Intel HD Graphics 3000.
What I've already found
I already did some hours of searching, and the main things I found are:
Downsampling is possible using Nvidia drivers (multiple tutorials available, see here and here), but these drivers do not show this functionality in my Optimus setup. Supposedly, this is because the Intel chip is in control of screen resolutions.
The Intel driver has some special kind of downsampling support intended for use on Netbooks. It only allows downscaling 1024x768 or 1152x864 to 1024x600, and doesn't seem to be properly documented anywhere. I tried this hack, and found no problems playing Battlefield on a scaled version of 1152x864. As the laptop screen is 1366x768, this was upscaling horizontally and downscaling vertically.
Virtualbox actually has a Scale Mode, but doesn't seem to run Battlefield 2 and has a listed known issue that the Scale Mode doesn't work properly when using OpenGL. VMWare, in which Battlefield 2 runs fine, doesn't seem to support downscaling.
At this moment, I think trying to make the Intel driver downsample is the most viable option, as I seem to get closest to the goal with it. Perhaps the Netbook downscaling hack can be enabled to support other resolutions as well. And even without the hack, the driver has no problems upscaling lower resolutions, so why wouldn't it downscale higher ones?
What I'd like to know
How to make my gaming laptop downscale 1600x1200 to a projector-ready or laptop-screen-ready lower resolution? Does anyone have experience with this? Can I try forcing my desktop to a higher resolution without breaking my laptop screen?