Geekzone published an interesting review of the Bluetake BT400 G5 Bluetooth Headset. The feature that stood out for me is the BT400 G5’s ability to pair with multiple Bluetooth-enabled mobile phones simultaneously. The reviewer was able to successfully answer calls on two phones, rapidly alternating between the two.
Although most of the practical applications for this are likely to be desk-centric (being paired to a PC for VoIP and to a mobile phone simultaneously), I could also see using this when my wife and I are travelling together in the car.