I'd just like to add my vote to this request. I've only discovered advanced installer today and have been very impressed. Allowing the version to be taken from the main executable would mean we could remove some custom build logic. Perhaps the product and package codes could be generated from a hash of the version string? This would also work quite nicely with the visual studio integration too. Changing the version number manually with Advanced Installer is something I would just not do, as it duplicates a change. If the installer product version were linked to the main executable, I may then sometimes create installers from within visual studio too.
I hope this makes sense. I wish I'd moved away from deployment projects sooner!