Well, this is nothing but a rumor but According to Eldar Murtazin, the next Nokia high end phones with Windows Phone 7 will be the Nokia W7 and Nokia W8. We know nothing about the specs yet. (As its still a rumor)
Eldar also says that as per Microsoft’s requirements all the Nokia WP7 prototypes are built upon Qualcomm Chipset. According to him, the Nokia W7 is based on X7 hardware base and W8 is based on N8′s hardware base. (As you can see in the picture above)
A dozen of Windows Phone 7 powered Nokia devices will come in the start of 2012.