Make a theme containing the directory structure:
Bundles > com.apple.springboard > SBBadgeBG.png
That's to replace the badge.
To change the position you probably have to setup an Info.plist (I don't know if this will work, but its along the lines of what you need to do):
Code:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0"><dict>
<key>BadgeStyle</key>
<string> [[[COLOR="Red"]left[/COLOR]]]</string>
</dict></plist>