Not to make fun of another persons idea, but this one gave me a chuckle at a time when I could really use one. I'm sure it's functional and easy to build,but looks like the fumes would be in your face. Looks like it may swivel, which would help.
It seems that back pressure would be an issue with that type of muffler. The more rich it would run, the more exhaust fumes you would get back in your face.