Yes you can simply install two video cards (one on AGP / one on PCI for example) & have a DualView setup. You will be a bit more limited in this setup as you won't be able to get the taskbar to use both screens (at least without a 3rd party application), you won't be able to have a proper video overlay on both cards & a few other setbacks.
It's still a good way to get familiar with dual screens setups though. Worth trying out.