I don't have a layout such as you describe, but I have used the MS Keyboard Layout Editor quite a lot making a couple of Biblical Hebrew keyboard drivers. Surely it's not really much work to swap a few characters around as you suggest. Do you have a specific layout planned?

Swapping the characters is itself a breeze, it�s the programming of diacritic combinations (e.g., accent aigu and all the vowels) that begins getting a bit taxing. Also, the fact that the Control modifier on all the alphanumeric keys only works in certain programs is bothersome. I guess I�ll keep plugging away. But if anyone uses Windows and wants a keyboard with handy quotes and correct dashes and Mac-esque diacritics, I can upload the layout somewhere (I also believe the Microsoft tool has an packager capability).