Actually JStrange, the hot key commands for setting Rally Points are still in the game from CIV III; I do not recall them offhand, but I have looked them up and used them in the past.
Actually, IIRC, the command for setting up a rally point is different than it was in Civ3. It's not just a hotkey command, you first have to click on the city bar on the main map. From there you Shift-Right Click on the spot you want to use as the rally point.