This thread is right down my alley!
To bring together warpflame death rays and (LoTR) burning eyes but keep it in reach of the existing range, what about a super heavy tank sporting a floating eye held in place by arcane machinery shooting death beams all over the place?!
Similar mounted on a Baneblade chassis like a Tower of Skulls, the top is covered by a chthonian machine focusing etheral energy to create an eye-shaped avatar of Tzeentch!
Beware his gaze directing towards you!
Half your model would be available already and rule wise it could take inspiration from the IG Shadowsword.
Aye, an conversion idea is already shaping up in my mind!