There are no X58 motherboards that have integrated graphics. The answer to your question is, YES you have to get a discreet GPU with an i7 system. The only current Intel chips that offer integrated graphics are dual core i3 and i5 chips. They only output video when paired with an H55 or H57 chipset motherboard. There are NO current Intel quad core chips that have integrated graphics.
Excellent! That's what I needed to know. So I can safely purchase a Dell system with an i7 & whatever their cheapest video card available is, get the system, uninstall and remove the video card and install my Matrox video card and be in business... correct? I know it should be obvious but the Dell tech's response threw me for a loop.