It's not quite exactly what you asked for, but have you seen the StackScripts from Linode? http://www.linode.com/stackscripts/

I have personally found that even distro-specific scripts require some tweaking across various hosting providers due to the default configuration of VPSs being different in each case. It has generally not been worth the effort for me to write complete bootstrap scripts so generic that they will work on anybody's VPS, but it's usually trivially easy to adapt whatever I have written to the quirks of a new hosting environment if the need arises.