pic - Execute instructions from RAM in a hobbyist-friendy microcontroller

One of my projects would greatly benefit from being able to run a program that isn't stored in the microcontroller (but is instead stored in a SD card).

So, I'm looking for a device that will allow me to load the code from the SD card into RAM and then execute the code from RAM. Currently, I only have the programmer that comes with the PicKit2, so I'd prefer to stay with PICs.

Does anyone know which, if any, PICs can do this? If no PICs are capable of this, then what are some different micro controllers that would work for this? Preferably ones that are available in a breadboard compatible package.

Answer

There are a few PIC's that allow you to add external program memory. I've never done this but Application Notes AN869 and AN778 has more information of how to implement the external memory.