The HTC Hero variant that landed on Sprint in October 2009 introduced Sense UI to the U.S. and had a elongated look with a trackball on the bottom of the phone. Of course, the HTC EVO Design 4G does not have the trackball and is currently available from Sprint for $99.99 with a 2-year contract. Buying the phone from Walmart will save you $1.11 with the same signed pact. Just make sure that they give you the HTC EVO Design 4G, not the HTC Hero.
source: Walmart via SprintUsersForum