It's almost trivial to interface an SD card to a micro controller, it takes up minuscule space and is nearly a universal standard nowdays.
In the case of a robot program execution speed is irrelevant, it should have all it's code for machine motion programmed on board, and then you just needs tokens to read from to execute the specific variables for that specific desired motion. This has nothing to do with a basic stamp where any program you wrote had to go through a byte code interpreter.