Can I have higher or widescreen resolutions (eg 1680 x 1050) in KVM?
Use the -vga std parameter while starting the VM to allow high resolution and widescreen displays. If the resolution you want to use is not available, you can patch the corresponding source files (see http://article.gmane.org/gmane.comp.emulators.kvm.devel/13557 as a reference), or send a mail to the KVM mailing list if you are not able to patch the source yourself. When using Windows as guest OS and not having issues with people violating the GPL you might want to use the driver from the VBEMP x86 project (http://www.bearwindows.boot-land.net/vbemp.htm) which is based on ReactOS code.