Take a look:
It works
. It needs better error handling (if AVS2AVI quits with an error, all you will see in the GUI is "Error" with no description of the problem) and more features (Stop button, a progress bar, the rest of the switches). It makes a .avi file with the same name as your .avs (but with the .avi extension, of course). Make sure to check "Overwrite destination" if you plan on testing with the same source file more than once. It only works with the special version of AVS2AVI included in the zip.
If you want to try it:
AVS2AVIDrop v0.1.0
Have fun
EDIT: I'm not releasing the source code until I clean it up unless someone really wants to see it...