Uploaded the power supply design to git hub today.  The supply is laid out in a way to allow either driving the system from the Arduino's 5V supply or using an external power adapter.  The Arduino's 3V3 supply is tiny (very little current, esp. considering this is the current you'll use to drive 80% of the stuff in any design), thus this design regulates the 5V0 rail from the Arduino or (via jumper selection) from a wall-wart (6V7 - 15V) and produces a proper 3V3 rail with heaps of additional current (3-4x the arduino).  Also includes a 1V2 core voltage for powering the Xilinx FPGA.  

Not particularly glamorous work but this supply also ensures that if you want nothing to do with the Arduino, you can still power the design and have a *very* low cost FPGA development board.  

Apologies to those that asked for this, I was traveling overseas.  Should upload the remaining elements shortly.