Cross-platform script installer

Does anyone have a recommendation for how to go about distributing an installer that can place custom scripts in the InDesign scripts folder (startup scripts etc) on both Windows and Mac?

It would have to detect what version of InDesign is installed and offer a choice if more than one exists.

I use a Mac, and I can create a Mac-only installer that accomplishes this, but I'm wondering if I can (relatively-easily) do something that works for Windows too.

The way I'd do it for a Mac would be to make a .app bundle that wraps the payloads and a ruby/python script that does the logic and copying. To do this for Windows would be trivial I'm sure, but I would stumble at the gui point.

So far, I've begun looking at a Java installer, http://izpack.org/, but I thought I'd check to see if someone else has a better idea before I spend time learning how to use it, as it's quite hefty for my needs.