Brian -
In the 7.0 version, we have the abiltiy for custom field values to be inherited down to children. If you fill in the custom fields on the parent before saving the structure, those values will be inherited to the children, and upon closing a child, if there are any higher level incidents that get created automatically, those new tickets will also inherit the values. Another part of this is if the child ticket has the same category structure and there are custom fields on the category, those values will also be inherited.
Let us know if this is what you are looking for, and if not, details on how you'd like to see things work are always appreciated!
Lisa