Nice scripts indeed. This is what called vivid community.

However my suggestion is to first try out solutions already embeded in your Ubuntu before creating new scripts, for something which has already been done and is supported.
The bash scripts are great if you want to mount/unmount from command line, but if all you need is to have this in nautilus, it could be not worth the hassle.

As someone has already written, since 8.10 you can right click on image file and open it with "archive mounter". If you need something more you could go with gisomounter or cdemu.