tenkan ura? if such exists...
I agree it sounds much like blending and stay center of movement. But use it as starting point for many techniques I do not get. At least not doing almost 360....
Actually, quite common exercise in many Aikikai dojos in the USA. Tai no henko is often then used to lead into techniques, sometimes via a full 180 degree turn or more...I personally don't like its use as a starting point for techniques because I believe it is very rarely done properly and just encourages collusive uke habits (as in "you mean it's NOT my job to run in a circle around you?")
Look at third version in this video: Darren, is this what you are describing? http://www.youtube.com/watch?v=I8dY2RhowoU