Developers mull 5,000-acre project for GM property.(Brief Article)

Two of the Valley's real estate powerhouses are considering joining forces to redevelop the General Motors Desert Proving Ground in Mesa, said to be one of the largest parcels to hit the market at one time.

Executives at DMB Associates and Sunbelt Holdings, among several developers that submitted proposals to General Motors, are discussing a. joint venture. They declined to discuss their individual plans, citing confidentiality agreements required by GM.

Another party said to be interested in the site is Del Webb Corp., but spokesman John Waldron also declined to elaborate.

"In a couple of months, I'd be more than happy to talk about it," Waldron …