I couldn't respond to your private message because of the "name" you registered under. Please go back and change your identity to something a little more descriptive than "_".
As for your questions, yes, AWC makes the Abraxas in .40S&W and I have a test report/article from Guns & Weapons for Law Enforcement from a few years ago. Worked very well in their test. I'm sure there are may other suppressor manufacturers that make suppressors that will fit the .40S&W. They also make threaded barrels available for use with their suppressors.
As for obtaining one from Earl or anyone else "WITHOUT any hassles",
that's an oxymoron. Title II/Class3 weapons = Hassle.
If you don't want the hassles, then you don't want to legally obtain the devices. For the best info on how to get started, go here:
NFA FAQ
Regards,
James