One possible workaround might be to use two monitors? I have three hooked up to my Xp machine, and each can use different resolutions, I generally have SE4 going on one, and have other stuff on the other two...with an open PCI slot it's quite easy to add a monitor (that is, if you have an extra monitor...)
My solution to this (since i'm computer rich and pci-slot poor) is to use VNC to run the SE IV on another box remotely. This gives me some signifigant advantages:
1. it's free (tightVNC is free, at least)
2. It leverages my network
3. I can run SEIV windowed
I'ts a little jerky, but not to bad, it's certainly playable and all that.