I am aware of:
<action method="unsetChild"><name>as</name></action>
Is it possible to remove all children in one line? e.g:
<action method="unsetChild"><name>*</name></action>
Or something similar..?
UPDATE - ANSWER:
<action method="unsetChildren"/>
Seems to do the trick reasonably well..
Don't be afraid to read the source file of the base block class.
Myriad answers in those methods.