For now this remains filed under rumor but TmoNews write “…our inquiries were not in vain as the Lumia 710 was discovered ready for a T-Mobile unveiling this January. The internal codename is “Sword” and is listed as coming in both black and white colors.” Now I don’t know what it means to discover it’s ready. Presumably they have some knowledge from someone in the TMo chain but I’d expect more detail than that.
Regardless, this is a low-end Windows Phone that you can expect to hit somewhere in that soft $50 range or so since it’s specs are similar to the Focus Flash. Of course, the colors should be popular with the kiddies and they don’t know specifications…but bright pink may sell.