Excel 2007. Also Word 2007. Is there a way to shrink the icon size so that
the ribbons remain but take up less "top to bottom" space?
try double-clicking on any ribbon-tab
or choose "minimize the ribbon" from the QAT options button (right-most)
(you will only see the tabs of the ribbon "optimizing" the space over the work area)
If you feel brave and have a few spare evenings, you might try Ron DeBruin's
approach as described here:
Best wishes Harald
But to answer your question, no you cannot change the size of the icons.