GM Corp. is accepting design proposals for a new mixed-use residential and retail area to create a downtown across from its vast Warren, Mich., Tech Center complex. GM owns a 312-acre parcel and plans on partnering with a developer to create a destination area for the city that would include housing, stores, and restaurants. Warren has no established downtown, and the area and timing are "correct at this juncture," says GM spokesman Gerry Holmes. GM's Tech Center is currently undergoing a $1 billion renovation and improvement project.