That is strange. I worked on the NPAC (Number Portability Administration Center) software. I also worked on WLNP. There isn't a technical reason why this won't work. Full number portability is supported in the US and Canada. Wireless porting simplified the process and eased the requirements to port numbers. My best guess is that, they would be able to port land lines in the not too distant future, once they meet the requirements for land line porting.