A Son Rises In Texas; Ross Perot Jr., the Builder, Puts His Stamp on Dallas
Profile of Ross Perot Jr, who has become largest real estate developer in Texas; says his latest project has been based on persuading Dallas voters that they should pay $125 million of $230 million cost for his basketball team's new arena, anchor for billion-dollar-plus real estate development that would include arena for Dallas Mavericks, offices and apartments; Perot Jr's vast real estate holdings detailed; chart; photos (M)