They won't haggle with consumers, but for large business customers the prices and other terms are absolutely negotiable.

All of them, in regions where they don't have a vertical monopoly. You can negotiate away installation fees and monthly package pricing on DSL, TV, internet phone... also sometimes get a no-contract deal instead of locking in for 24/28 mths with the dreaded ETF which is a large part of Comcast's profitability.