Guys dont do a Nand backup of one phone to the other. You will destroy your 4g Wimax settings. If you have done a backup with the new Amon 1.8 which saves your Wimax settings as an image file it will overwrite your new Evo settings. Then it will be hell to get it back.
If you are brave enough I say first do a nandroid with Amon 1.8 of your current rom then remove the wimax.img from your current rom and place it in the nandroid folder of your old Evo and delete the wimax.img of your old nandroid. Now I am only guessing this will work and don't see why it would not but be careful you could screw something up real bad.
Another option is MYBackup Pro works great for all your needs and no need to worry about 4g being broken.
Also Amon has that warning on his front page if you go to download his recovery
[Recovery] [28-August-2010] RA-evo-v1.8.0 - xda-developers