Hi Allan-
I've done some digging, but unfortunately don't have a solution for you. The number of items displayed in the scroller is controlled by the "Products per page" setting in the Admin/General Settings/Appearance. You could increase your setting, but of course that will affect all of your category pages as well. The critical piece of code that controls how products/pages are divided up is in include/search.php under
Code:
# Prepare the page navigation
but I wasn't able to successfully hack this so that the "Products per page" setting was ignored for featured products.
-Glen