I've seen lots of eGPUs that run desktop graphics cards, but are there any designed around a mobile one? You might be asking why would you do that? The answer, portability. A desktop eGPU is quite cumbersome to take with you, but an eGPU built around a mobile GPU would be far more portable and easier to power (possibly over USB). This would allow you to turn your thunderbolt connectable ultrabook (read razer blade stealth) into a real gaming notebook while keeping it light and small. This would also allow for a far more portable eGPU, to allow you to game on the go when required.