You can pick up older Subarus (1st gen Legacies, GLs, XTs, etc) for under a grand and rwd conversion is as simple as welding a diff and removing front axles (although there are ways to convert and keep the front axles in as well). I'm biased from having a drift-a-liscious BC Turbo Wagon, but Subarus are overly tough and have a lot going for them:
Good balance (symetrical design)
Mad torque (at least from the 2.2 and 2.5 motors)
Long wheelbase (103+ in)
Parts interchangability (the same basic technology in all models up through around '95)
Good steering angle
Good Polar Inertia (engine over front axle, plenty of body over rear axle)

A GL or XT would be one hell of a sleeper drift car too


If you want to go the beaten path/tried and true/boring route, at least do something somewhat origional, like a Ute S13 or a SOHC block/DOHC head with twin Webber side draughts or Keihan FCRs or something...