There are more than a handfull in the yadkin, forsyth area with shied built motors pushing well into the 1300hp+ range, granted they are all 12v's and strictly pullers. There are many more in our area that running 600-700hp daily driven trucks but they are mostly cummins powered trucks. Generally the common rail and electronic trucks make power more easily but are typically a little less reliable (electronic parts like injectors), but you cant beat a 12v for good numbers and reliability.
One thing ive noticed while doing research is the cummins seems to make more power on stock components (stock rods, pistons, ect.) than duramax or powerstrokes. Not saying they cant do it just seems they tend to be built more at the same power levels.
Gus Farmer runs one of the highest horsepower vp powered trucks in the country and does it with a good amount of reliability. I think the last numbers shown were like 850hp which is a good number on a vp truck.
In the end if you want to see big numbers check out some shied built trucks like Let It Roll, Sleepless Nights, and I cant remember the name of Faith Millers truck but her and her husband run trucks. Jaquelin that runs sleepless nights and her dad has a truck to.You also have trucks like Tim Vestal, and the Brandon Farms truck and these are all nc trucks and local to me. Its amazing how many high hp diesels there are around.