There are lots of examples but I'll name a few.
Well you mentioned Justin Rader and he actually developed it based on his 1st ADCC submission loss to Rafa Mendes. Rafa uses a head and arm control from top half to roll behind the head, free the guard, and then uses his top leg to smash down and trap their arm deeper for an anaconda/brabo/guillotine series or to just take the pass.
Lachlan Giles is a great recent example and has an entire instructional on this and here's a good video of him using this style a handful of times in one roll. Lachlan's student and training partner Craig Jones used it a ton this past ADCC. He alternated between a lot of arm-in guillotine, brabo, and high elbow guillotine off the floating pass.
In this roll it looks like Giles gets 5 or 6 front headlock chokes. All while using them to pass.
As for a couple of older examples...
Marcelo Garcia used this style a lot but instead of trapping the head and arm like Rafa, he only trapped the head for the high elbow guillotine and/or to pass.
I know it's not an American phenomenon but honestly a lot of Americans are standing out to me. Edwin Najmi and Josh Hinger are great current examples that use it both gi and no-gi.
Other Americans that use/d it often are Jeff Glover, Bill Cooper, Ryan Hall, Rafael Lovato Jr, Garry Tonon, Tim Spriggs, Dillon Danis, Oliver Taza, John Combs, Geo and Boogey Martinez, Keith Krikorian, David Porter, and William Tackett are other good examples to study.
Claudio Calasans, Leo Vieira, and Cobrinha are Brazillians that used to to great effect.