Take (4) HDMI or Component Inputs and output a single splitscreen?

[TwistedLincoln]

Does anyone know of a device that can take four inputs (either HDMI, or component video will work) and output a single HD signal with each of the input signals as a single splitscreen output?

I've seen several devices that will do this for SD signals (usually used with security monitors, it seems), but nothing that will work with HD.