Can Arduino MISO be set as output?
If you want to use the SPI module built-in to the microcontroller, you have to use the pins they choose.  They are hard wired.

However, you can also use the same pins as general purpose I/O, which means you can bit bang it instead of using the SPI library, but that is significantly more work in the software.  You might be able to find an existing library somewhere to help you, but personally I would spin or mod the PCB and call it a lesson learned.