I half-jokingly tell people that we have a limited number of breakfalls in our bodies...
Nadeau sensei and Toribio sensei usually do their ukemi classes at the San Rafael Retreat in Northen California each summer. It's a fun class which provides people with different ways of looking at ukemi no matter how experienced you may be.
My personal thought is that ukemi should be taught just like any other "techniques" like ikkyo and shihonage. I think that there are plenty of ukemi techniques that people should know.