Well, in the travelers mod you do get immortals and you can get tons of them. However, they die of old age after only a few years (probably makes them great targets for wind of death) and most of them aren't very good at killing, so they're more like an endless wave of chaff. Some of them do get mind blasts though. All in all I didn't find the immortals themselves to be overpowered, but maybe if I had used more battle magic they would have been (though amos' mods tend to have pretty poor artillery mage potential, and I think that's one of them).
The immortals in llamabeast's tomb kings aren't bad either. They're sacred medium infantry, possibly heavy infantry equivalent for the age, but it takes a lot of work, gold and gems to make very many of them and just building them is not a winning strategy. I should know because llamabeast is proving it to me right now in the warhammerama game
