some of them have pcie 16x slots, but you knoe laptop ram slots those weird slots.. pcie 16x is like that on a laptop. So its upgradable. But one problem is the heat.
Tell me this...how would a standard capture card even fit in a laptop?
With a laptop, you're limited to USB and PCMCIA. Some have special AGP/PCIe slots inside, but cards would be incredibly expensive and there aren't any just capturecard upgrades for them