I have written a script (with the help of James Sorenson) that allows AppleScript to execute shell commands containing high bit characters via the Terminal. The script additionally allows a very long sequence of commands to be run.

Please be careful with this for the time being. I have only tested it a little, and I would appreciate any input.

Download the Script

Note: The script passes the commands directly to the terminal, so you need to properly quote and/or escape the strings beforehand. Check out this hint for a way of doing this.