@alarnold, I don’t know if this would work for you or not. It requires a tripod and some hardware. If the goal is to shoot a building, inside a train station for instance, eliminating people can be done with a couple of dark ND filters. An exposure taken over a few minutes will result in almost everyone disappearing because they move enough that they don’t register on the long exposure. Since the building doesn’t move, it is sharp, and empty. If the goal is shooting water drops, or some other object that is moving quickly, you can use a fairly slow shutter speed and freeze motion with flash. Small flash works better than studio strobes because the duration is shorter. They make flash brackets that hold three or four small flash, the shoes are all fairly close and the units radiate out, this makes several little lights into a much larger light, and potentially a much brighter light. The built-in diffusers cause the flash to zoom to minimum focal length, but you could use plastic diffusion domes to minimize shadows from the individual flashes. My Nikon umbrella stands are pretty spindly but the stands for my studio strobes are heavier tubing and have a larger footprint. With heavier stands and no sails to catch wind, you could probably forego sandbags. If you just want to light from one side, you could forego the stands entirely, some time during a long exposure have your subjects walk into the photo and pose, then hold up the flashes and fire them. After the flash, your subjects can leave the scene. You want to aim the flash fairly tightly, so the spill goes out of the picture. Being outside, reflection should be minimal.
If you think this could work, instead of just being the ravings of a mad man, you might want to rent the gear for a day or two, to experiment, instead of purchasing it all. A set of 4 flashes, the brackets and a stand will probably cost around $2500! There are some inexpensive Chinese flashes that might work well for this and would reduce the cost a lot. They have a slave mode, so they fire when they see another flash, which could be good or bad in an area with a lot of tourists taking flash photos with their P&S cameras.