I have seen satellite tornadoes, all of which were on May 29, 2004 on the Beloit-Belleville storm. They formed on the periphery of the violently rotating mesocyclone and appeared to be rather weak. Sorry I don't know more about how they form, but I would say that before we can distinguish between how different "types" of tornadoes form we will have to gain a better understanding of how tornadoes form in general. Perhaps there is someone else in the group that is a little more versed on current theory, I have been out of school for 10 yrs now and I know that the science has come a long way since then.