A MetaFilter list of suggested “sprawling post-modern novels”.
Off the top of my head, I have these that are on their list.
delillo’s underworld
infinite jest
house of leaves
Umberto Eco’s Foucault’s Pendulum
Rushdie’s Midnight’s Children and Ground Beneath Her Feet
Death on the Installment Plan by Celine
Neal Stephenson – Cryptonomicon
The Tin Drum