Any more controls and functions, I reckoned u'll need the wireless transmitter, WFT-E2/3/4.
WFT-E3 supports 40D, think WFT-E2 supports 1DMk2 while WFT-E4 supports 5D? However no one transmitter can serve all ur 3 cams though.
Live-view mode viewing, camera settings (shutter speed, aperture, WB), etc can be done via the PC onto the camera.
Good thing is that it's wireless, no need to meddle with long strands of USB/FW cables.