So I designed one up: http://www.thingiverse.com/thing:297757. It re-directs the air to the cooling fins on the extruder. The idea is that it keeps the cold end and the peek a bit cooler so that it prevents jams.



I'm not too sure if it is any more efficient than just increasing the fan voltage to 12V (Like I have already done). I did notice that it now produces a bit of back pressure on the fan.
I did measure the temperature of the peek at the top, middle and bottom and it is about the same as without the shroud.
Anyone else want to give it a go and let me know if you think it is of any benefit?