I stumbled across this Video yesterday from someone to whom I am subscribed on youtube.
The guy they surprise says Mitsubishi like I do. I pronounce it Mitsu-bih-she. First time I have heard someone else pronounce it like that.
I have also heard:
Mitsubeeshee (most common)
Meetsubeeshee
I also pronounce Nissan wrong. I say Nissin not Knees-on.