Open letter to Microsoft and Macrovision re: MSI's and other installation packages

Hello Microsoft and Macrovision -- especially you OneClick, WindowsInstaller, and InstallShield people out there. I'm the guy who makes the calls on both of your products at one of your corporate customers.

I want a tool I can run on an existing package which I attest works perfectly on XP SP2 (or better yet, W2k SP4). The tool will tell me whether or not this package will install correctly on Longhorn. Better, it will tell me whether the application will function as intended. Better still it will tell me what configuration changes need to be made, whether to the client or the OS config. (Would it be too much to ask that these changes can be automatically implmented, outputting a new package that includes them all? Oh, and if you're going to automate it, you'll use, and allow an optional export of, an XML manifest with a published schema, right?) Thanks!