Hello,
Yes it is possible but messy. You will not have the ability to run the Vista ICE validation Suite. It will also be messy in Vista terms too. It would be missing several things that Vista wants. For example... the manifest that tells Vista what execution level is required wouldn’t be there.
But Vista would most likely treat it as Requires Administrative level and run it. This also does not mean the product inside the MSI will work correctly only that the MSI would run.
If I come up with something more substantial I will post again but this is my first take.
Thank you,
Bill V.