I guess it depends on your definition of what streetable is. Mine would not include feeling like a clutch slipping when below the stall speed & under load.
And it has everything to do with physics. To get higher stall speeds, you reduce the c'ter diam. Don't know of any 12-13" cters with 5000 stall speeds. The tq to drive the the car comes from the centri force generated by the fluid exiting the turbine inside the cter. Big diam cter, bigger turbine, more centri force. If the cter is smaller in diam like a 9" 5000 stall cter, less centri force is generated & slippage occurs until the stall speed is reached. While I haven't mentioned the other parts inside the c'ter, the above is the physics of how the initial fluid force is generated.
