USB Video Card?

I just bought a new computer with the latest graphics card hoping to hook up my multiple monitors to it. When i tried to hook it up i could only hook up one monitor to keep the SLI mode in the video cards. I wanted to add more video cards so i could hook up 3 more monitors but all the computer's PCI Express and PCI, AGP slots are full and there are none availible. The magma pci expansion is just to expensive for me then I saw on the internet that there was a usb external video card that would probbaly work. I am wondering if anybody has tried these with Flight simulator and if they are hardware accelerated. I dont need it for views just to display different instruments like the GPS or NAV/COM

thanks for your help 😀