I am gutted. My idea for a megaphone helmet has already been done:

(Mine [the one in my head] didn’t have the iPod on, just the microphone, mainly for ordering drinks at a bar.)
UPDATE: idea from Simon: this would be perfect for walking around Wan Chai, shouting “Sod off Swampy!”
superb i want one.
A few modifications and it would make the ultimate headset for a mobile phone. DOM Jolly, watch out.