Went out yesterday and impulse-bought a
Logitech G330 because I just *happened* to be in JBHifi. Under a hundred bucks - but now I find some sites are promo-ing it for $35 :/
Irregardless; I tested it out on last night's MAG session and it worked really well. (That is, noone complained that I was making a racket...)
It's got a USB card adaptor with it, so I plug the mic into the PS3 USB port, and the headphone plug (3.5mm with an adaptor) into the headphone socket on my amp.
Set the PS3 to play voice sound thru the main audio device and Viola! MAGging with no nagging.
And I still get to use my Cordless Vantage for the other PS3 on the big TV.
Happy.