I'm not aware if there are specific skins that will change the way your toolbar looks, but you can use third party themes.
To use third party themes, you used to need multiple programs, but now you simply need one. It's called
Windows Theme Installer.
Simply download this program and a third party theme of your liking and use the program to replace the files that the theme includes. You can find third party themes many places, my favorite resource is
deviantART: where ART meets application!
Keep in mind that you may have to use task manager to end the process "explorer.exe" when replacing the file(s). Once you've replaced the files you'll probably have to restart your computer.
My favorite is a transparent theme called Soft7 by an artist called AP Graphik
Here's a quick tutorial on installing a theme:
Turn off User Account Control
Download Windows Theme Installer
http://www.thewindowsclub.com/windows-themes-installer-install-windows-7-vista-themes-easily
Download Soft7 1.8
http://ap-graphik.deviantart.com/art/Soft7-1-8-for-Windows-7-144948406
Extract Files from both downloads to a particular directory
Open Windows Theme Installer
Right Click Taskbar, Open Task Manager
Select Explorer.exe, Click End Process
Alt-Tab to Windows Theme Installer, Direct Program to all relevant files
(Some themes include replacements for explorer.exe and explorerframe.dll and others. Other themes do not)
Install the theme and relevant files using Windows Theme Installer
Restart computer by pressing Ctrl-Alt-Dlt and choosing restart from the power menu.
Once your computer restarts, your theme should be installed.
