id Software is relocating from their Mesquite, TX offices to Richardson, TX in spring of this year. This was actually reported some time ago, and there's a follow-up here saying they are moving 250 employees to a 57,000 square foot space covering two floors. Other developers in Richardson are id collaborator Nerve Software and war game developer Presagis, and the new location is under 10 minutes from the Plano, TX offices of Gearbox Software. Thanks Redwood.