I do not know of any Quick Style sets (saved in .dotx templates) that have
been made available on the internet. Someone else may know of them. But you
do have hundreds of different potential combinations built in to Word 2007.
You've probably already tried the 10 Quick Style sets (Home tab, Styles
group, Change Styles, Style Set) included with Word 2007 other than the
default Word 2007 set (all can be live previewed).
In addition, you can experiment with changing the theme fonts (23 available)
and/or the theme colors (21 available) with *each* of the 11 Quick Style
sets; you can experiment with these on the Home tab, in the Styles group,
Change Styles, Fonts or Colors. Mixing and matching different theme fonts and
theme colors with the 11 different built-in Quick Style sets creates hundreds
of different, coordinated combinations.