What i like, is the idea of buying Lich's, Runeglaive, AND Iceborn. Lich's damage on single target, Runeglaive damage on AoE, and Iceborn's slow AoE. All on one hit. And it makes a fun build for an Archangel Staff too. Add a Luden's, a Rod of Ages or an Abyssal Scepter to the mix, and you're good to go. Hell, any AP item would work at that point.
I'm saying this might work because currently Lich's and Iceborn's damages don't stack, Lich's takes priority, but the AoE slow of Iceborn still procs. Assuming that's the case, i think it's safe to assume Runeglaive's AoE damage (excluding the main target who'd get hit by Lich's higher damage) would also proc since it's a different effect.
In Lich's and Trinity's procs, i'm not sure but i think whichever one is strongest applies to the single target. I do know both can't apply at the same time.
*Edit: Not sure it'd work because i just counted it out, Seraphs, Runeglaive, Lich's, Iceborn's and Ages together would give at most around 380 AP. That's pretty low, even if the procs would be sweet. Could always take a Rabadons i guess?