I agree, if richmond and uptown never get built then go full bore a subway from like Voss & Westheimer to DT with stops at chimneyrock, galleria, weslayan. Then curves NE with a stop at Shepard and Grey, then w dallas & waugh and then allen pkwy and montrose then memorial and houston finally in DT at Capital & Main. 9 miles about
http://lightrailnow.wordpress.com/2014/02/13/new-subway-metro-systems-cost-nearly-9-times-as-much-as-light-rail/
I would guess 450mil/mile so 4.05 billion. Slightly lower construction cost in Hou.