The only mention of these I could find on a short search is this http://www.stenudd.com/aikido/aikido...hiwaza-mae.htm which states that Kaiten Osae is rarely considered a standard technique. I can't find pictures or a description, so I can't verify this.

Anyway the SBGi use of the underhook has very specific goals and methods, and is an important part of the whole clinch game. I don't find it credible to claim that this situation is analogous to an obscure technique out of hundreds that may be seen once in a blue moon in particular Aikido schools.