As posted in the "Game Consoles" faq, the answer is yes. All those consoles have the ability to output 15khz rgb in one way or another. SCART is the prefered method.
I don't want to tick anyone off by mentioning this, but it's on-topic.

For anyone interested, I have full RGB SCART cables for many systems available at my store. These are the best base to start with for what you want to do. If you don't use an RGB SCART cable, regardless of where you get it, you will need to solder wires directly to the A/V connections on the main board. I don't recommend this for obvious reasons

Also remember that not all SCART cables are created equal. As all outputs are represented in the connector, they could be Composite, S-video, or RGB only. Make sure you check beforehand.
RandyT