Here's something offered by my music guru:
One name for anyone that wants to see some serious blast beating, Flo Mounier. However, he has taken it up several notches to hyperblast beats.
Blast beat is in the 180 bmp, while hyperblast is 260 to the extreme of 400 bmp.
What makes Mounier different is that he incorporates elements of Jazz and Latin drumming into his style.
There are several videos of him and his group on Youtube.
One more point, he is not really not that big or even that muscular.
And Immortal isn't even together anymore. Also until Horgh joined the band the drum position was straight out of Spinal Tap. Immortal was the two guitar players and a revolving door of other musicians for their recordings and tours.
This is what Horgh looks like these days. The funny part, is they got all dressed up for these pictures, several years after the band broke up. He's the one standing.
http://ruthlessreviews.com/pics5/bm2/bm8.jpg