[GadgetKen]

While it's 4 sims active, only one of them can actually be on a phone call at any given time. Since I don't make a lot of mobile phone calls (<10 minutes/day; and often as little as 3 minutes) and the maximum output is only 6/10's of a watt, I'm not overly concerned. Plus if I use a bluetooth headset, the phone is not near my head (but then of course a bluetooth headset is also a type of weak wireless transceiver).

Excessive battery consumption I think would come more from using the FM radio or TV receiver, or the standby mode of having 4 GSM sim chips in the phone (mostly standby receive with very brief "I'm still here" data packets to the mobile phone network). Newer multi-sim Chinese mobile phones are using single transceiver integrated circuits from Spreadtrum and others so this may actually be fairly thrifty with battery consumption.

For a phone with truly questionable health benefits take a look at this mobile phone/cigarette lighter hybrid: 6208C Dual Sim Quad Band Touch Screen Lighter Mobile - eBay (item 260682246239 end time Oct-30-10 13:51:22 PDT)