I guess any type of A-B switch could work (such as those used to switch between two serial ports). A 9-pin serial version would have enough connections, and these can probably be found for very cheap. I expect that if they work fine for high-speed data they would work fine for a video signal. But don't take my word for it as I have never tried it.
I believe that there was a thread a long time ago about using an A-B switch to switch between multiple PCBs. As this entailed switching the power as well as the video, sound, and controls, it was recommended that this not be done. But since you are only switching the video, it should probably work fine.
Mario