Is the Add Page command for Layouts accessible in functions?

Is the menu option "Add Page" for Layouts available within functions (other than through the execute menu path)?

If not, consider this as a feature request to have NewLayout include a /PAGES=(N) flag.

Yes:

LayoutPageAction/W=$layoutName appendPage

Although you need to keep track of how many pages, and tell Igor which page you want to add items (and pages are 1-based!)