If you want to stay in the 4" category, then take a look at the Samsung Galaxy Light. It's a quad-core 4" phone. It's not the snappiest phone out there, but it's not bad. It was on sale at Wal-Mart for $50 last week, but it's available for $100 through T-Mobile with no contract.

http://www.t-mobile.com/cell-phones/...axy-light.html