Starting this post now and I will keep it up to date with any additional information I find.
I will be picking up my first au IS03 tomorrow and will start probing this phone to see about obtaining root access on it.
After extensive googling about the phone, the only real information I can find is on the sharp website itself:
This is for the usb ADB driver to debug android in place on the phone via the android sdk.
The IS03 is running an au customized version of android 2.1 and my ultimate goal in this endevour is to create a custom image for the phone using either android 2.2 or 2.3 with enough backwards support to run the bundled au apps (seifu keitai, 1seg, lismo, etc..)
Stay tuned to the android category on this site for progress updates.