Joe:
Generally if you are going to use a current controlled driver on one side of the LED you would use a simple switch type connection at the other side. For example if you were to plan to use a controlled current sinking type driver at the LED cathode side to GND then it would be best to switch the high side (LED anodes) to the positive supply rail with a saturated switch such as a BJT or MOSFET. Such switches are available in either integrated chip form or you may choose to use low cost BJT transistors in a discrete circuit design.

You would want to avoid trying to use controlled current drivers on both the high side and the low side.

Michael Karas