I just got the PSX controller (It's generic) working with the Maple's Hardware SPI at SPI_562_500KHZ, SPI_281_250KHZ, and SPI_140_625KHZ. I didn't try any other speeds. Part of the problem I found was the delay between sending bytes was too short for the maple (maybe for the Arduino, these delays are longer for some reason, but won't go into it) and the delay of 15uS between bytes allowed it to work at higher speeds. The reason why this happens is because in a playstation, there is 1 more signal it needs, the acknowledgement signal. It flags when the controller is ready for more data, in all of these examples/libraries, it's not waiting for that and is setting a delay for long enough to allow the controller to be ready. It's also not known why there needs to be a longer delay for the higher clock speeds, however it's not something I'm going to investigate since I've had this hardware longer than I should have (I was only meant to borrow it for a weekend previously, but had it longer due to other commitments with university).
Also, When I read the original code again, I realised that the controller wants SPI Mode 3 (clock line idle high and samples taken on rising edges). This was an error because I didn't have access to some reference material at the time I originally looked at it.
Lastly, the circuitry I'm using will be slightly different to yours as the breakout board I borrowed contains a 74HC541N to buffer the signals between the original board it was designed for (a Digilent Spartan 3E Starter Board) and the controller. However, this should not affect the library working for you. There is still a bit of code cleanup to do, but this is the library:
https://github.com/crenn/PS2X_lib_maple