They appear to have custom instruments on at least some of the videos. Guess regular celli would not take such a beating. They completely destroy their bows, but that might be for show as well.
So surfing around I came across these 2 teenage brothers that are sort of simulating 2Cellos in their own way and it's fabulous. They even have the attitude and schtick down to a T when 2Cellos had them perform live with them during a tour last year. They were finalists on Americas Got Talent in 2014 and are mentored by their grandfather who was a renowned Celloist in his day. By the way, age 13 and 16 in these videos.
Push this first one to 1:30 mark and jam out on some Purple Haze
Here is Emil and Dariel doing Smooth Criminal after being introduced by 2Cellos-