No, it is not currently possible to set the task manager image name via a command line switch to pythonw.exe. Issue 5672 and others cover discussions about doing so.
There are some projects focused on making this possible from within your python program, like py-setproctitle. I haven't played around with them.
The Java solution is to create a launcher, either one that embeds all the Java code with the bootstrap interpreter into one exe or one that acts like java(w).exe and points to your Java classes. There are similar projects to do the same for Python like py2exe.
A simpler way to change the image name and "make your own launcher" is to make a copy of pythonw.exe named whatever you like, eg. mytask.exe. I have tested this with the copy/renamed exe in the PythonNN directory and in other directories and it runs fine and changes the Image Name in Task Manager. I haven't tested it from Task Scheduler in WHS2011.