NewTek TriCaster is the gold standard current for a broadcast video mixer portable, live with all the bells and whistles that might require a live production. I use a TriCaster 455 and 855 for many events and produce really have few complaints.
The relatively new TriCaster 8000 (retail $ 40 000) develops on the sets of features from previous models of Newtek. As the 855, the 8000 can simultaneously manage eight HD - SDI video sources and save each ISO separately. The 8000 develops their virtual sets, transitions, animations, media players, and integration of live streaming.
I asked a rep of Newtek, what is his favorite of the 8000 feature and his response was the integration of social media. You can apparently make quick clips of video or still images and push Facebook, YouTube and Twitter all from the TriCaster control interface. I guess that if you're a lean operation and you have a guy doing everything, then I suppose it has meaning. According to my experience, everyone who is to lead and to a live event, will have its hands full of everything.