So I installed Windows 8 in VirtualBox, the host machine is laptop with 1280x800 screen resolution. Running a guest not in full screen only have 1280x736 real state. In this configuration, I am not able to run Modern IU (Metro) apps. See below for the error message.
Not able to run "Store" app
It seems like Windows 8 requires at least 1024x768 to work with the modern applications. This is interesting because they are making fun of original Android tablets as not flexible, like you know running weird screen resolution. The layout capabilities of WPF applications is suppose to be flexible, what's going on Microsoft! So this also means that netbooks with smaller screen will not work properly with Windows 8.