I cant help but think that good ol' Pillage would be a better overall choice than Rain of Rust, even with the silly Spellbinder gimmick.
As far as the benefit of the rest of Magic is concerned, gold cards in Legends were executed perfectly. They got all the excitement a designer could hope out of a splashy new mechanic without using up any of the valuable design space. Truly amazing.
--Aaron Forsythe's Random Card Comment on Kei Takahashi
If you want to build a deck around Lich's Tomb, you should go for something that actually needs Lich's Tomb, and only Lich's Tomb, to work. Other Lich effects are heavily Black, so any deck purely in that color doesn't need the Tomb, otherwise I'd suggest the hilarious Hoarder's Greed. Instead, we need a nonblack effect that rewards us for making lots of guys die, so that the sacrifice of our Darien tokens is the real point of what Lich's Tomb is supposed to accomplish, and being immortal is simply a pleasant side effect. I'm thinking slap Indestructibility or Red Ward on Darien, then combo off with Pyrohemia and some bottomless well of red mana (there's probably a way to parlay infinite creature deaths into infinite red mana but I can't think of it offhand). You can then imagine that your mage's strategy for the battle is to seal himself into the Tomb with invincible Darien sitting on the lid, coughing up fiery doom to roast the entire world for several thousand damage points as the entire population of the plane rushes to defend their King only to become new hosts for his fiery disease. Take that, Archenemy!