ID doesn't seem to copy any files outside of it's installed directory, so why can't it be "portable"? I don't mean "leave no trace", but just be able run without going through the installation setup it's very much possible. Install it to a flash drive and launch it on any computer.
From what I can see from installation log, all it needs is register ShellIntegrator64.dll and install service. All this doesn't require an installer, it's just needs a few lines of code (2 lines in CMD). Sure, it requires administrative rights, but that can be requested when first launch, and even clean up after it's exits (I think the service should have enough privileges to unregister dll and uninstall itself)