Dual SIM Windows Mobile 6 device
If you are looking for a Dual SIM Windows Mobile device then the General Mobile DSTW1 device might be of interest.
It has 2 SIM slots - one which supports quad-band GSM (850/900/1800/1900MHz), while the other offers tri-band GSM (900/1800/1900MHz). Both slots support EDGE mode for data transmission.
You can get more details from WindowsForDevices.com