I was told that someone was looking for a meteorologist...I have two degrees in metr. and now have a job in the field, so I'm official now
I'm also an avid stormchaser--I've seen around 20-30 tornadoes this year alone, including Greensburg, KS (May 2007). I've never seen so much devastation as with the Greensburg tornadoes...and they were actually "lucky", as an even larger and stronger tornado barely missed the town!
Tornado formation is indeed not very well understood (we need better instrumental observations, but there is a serious lack of funding in our field)...but what you're probably looking at in the video is that the condensation funnel (the part you can usually see of a tornado...it's actually cloud) does not extend down, so all you are seeing is the debris, which makes the tornado visible. Technically, a tornado is when rapidly rotating air reaches the surface and debris is moved, or when the condensation funnel reaches the ground. I've seen some tornadoes that never do have a decent condensation funnel, but have a lot of debris that gets pulled upward.
I don't think anyone can really tell you if you're right or not about tornado formation, not even the people who study them all the time (though they may say otherwise)...we have numerous theories and are trying to get more observational data, as well as trying to create them in numerical models. There is so much to be done still...metr. is still a young field with billions of factors to take into account.
VORTEX 2 was recently funded, so hopefully, they will be able to find out some more about how tornadoes are formed. I'm not going to attempt to explain what the current theories are...don't want to scare anyone off the boards! My husband actually does tornado research and found that some of the common indices that forecasters use to forecast tornadoes are rather useless...but he's found a way to use weather data to better forecast tornadoes--at least distinguishing between tornadic and nontornadic supercells (rotating severe storms...the entire cloud rotates). Most tornadoes are formed in supercells, though they can also be formed in squall lines, etc. The long-lasting, usually stronger, tornadoes almost always are associated with supercells. The video shows a supercell tornado.
If you're interested in seeing more tornado videos and images, check out the following links:
http://tornadovideos.net
http://ounhat.com
On YouTube, look for the user ID TornadoVideosdotnet...this guy gets some amazing footage! Reed Timmer is his name (he's a friend of my husband) and he prides himself on getting as close as possible. He's the real life "Extreme" from "Twister". He's also a PhD candidate and a brilliant scientist. Thankfully, his chase partner makes him back up a bit, so we don't lose such a young scientist too soon. I refuse to chase with him...too close for my comfort! (And I've driven through an F0...actually, a landspout)