I wasn't sure about the idea of riding a freewheel with only a front brake, but have to admit I like it. While taking it for a spin, it occurred to me that it would be an interesting option to have a fixed wheel bike - with a clutch. It could be a lever (like a brake lever) or even a set up on a gear lever like the old 3 speeds with a neutral.
Why? Well for a start, you could corner much faster. (If you've not ridden a fixy before, you have to watch the pedals hitting the ground when you corner). Riding over significant bumps on a fixy is also an acquired talent, being able to drop the drive out and coast now and again would help. Another thing: after stopping, you could align your pedals for take-off.
I know that for fixy purists it's an ethos thing -'commit'.