Heres a link for minitruck drifting in Japan for those of you who are interested......... http://www.youtube.com/watch?v=dlKT7ixyoSk&feature=related
check this one out! The mini is beating the pants off everyone in the race! http://www.youtube.com/watch?v=XuD3VdSID-4&feature=related
My guess is a motorcycle engine swap. There are youtube videos of Hayabusa kei trucks... BRAAP BRAAP.
This video only has one clip of drifting in it, but has some other interesting things in it, like some accident shots... http://www.youtube.com/watch?v=4bJKQZIjOS8&feature=related