Hi Steve and Rudo,
Steve's right in that you can't do anything about the layouts that are
provided with PowerPoint in terms of what is on the formatting palette
or available in the Format > Slide Layout menu.
But you can copy, paste, duplicate change size, and otherwise fiddle
with the layouts that are default and turn them into whatever you like.
Save your customizations as a presentation. You can copy the customized
slides to any other presentation from slide sorter view.
-Jim