I'm not an expert but if i'm not mistaken then bands 13 and 17 are subsets of band 12. If that is indeed the case then wouldn't it be easier to just tell VZW and ATT to use band 12?
Are you talking about a complete spectrum reboot across the board or just a few bands that have to do with wireless? If you want the former I think it might take longer than 7-8 Years.