Two Entropic boxes 'Octagon SF2028 HD Optima 3D' and the turkish 'Next Machina 3D' are the first satellite receivers with a MultiPiP feature.
MultiPiP can display live and simultaneously till 16 live channel windows
I made a video to show how MultiPiP concretely looks like
PS.
SF2028 have a closed source OS, but Octagon have currently in development high-end Linux models with triple and quad tuner support.