Smoke pots. The cheapest and simplest way is to use 55 gallon, steel drums. I get them up in Memphis for $6.00 each at a container recycle place. That's for larger areas. The design can be simple using steel lid/band clamp fasteners. You can punch some vent holes in the side (cutting torch is way faster) and some holes in the lid (three times more than in the sides). Keep the holes smaller than 1/2 inch to prevent sparks from wafting out. 1/4 inch would be even better. The best smolder material in these parts is pine needles. They smolder and smoke like all get out. I don't know what would be best in your parts. You set them up wind and at sensible intervals and you can smoke up a big battle field setting. Pine needles will smolder for a couple hours to half of a day long. The down side is that they take either water or time to put them out. Plus, you can't move them until they cool off. When the production's done with them, take them out to a scrap yard and wave bye-bye to them. If you just have to and don't mind that smokey smell, you can store them somewhere for future use. I mean like on someone's land. Don't put them in a storage building because the acrid, smokey smell can get into everything. They can rust for years in a field before becoming dubious for use. I've heard of people putting squirrel cage blowers on them to get them to really pour out some serious smoke. The designs you come up with can include adjustable vent holes as well. I don't know how big you are on DIY. Maybe some of your handier crew has nothing better to do on some days. Sounds like a job for the grip crew on the grip-less days.
I'd make up at least one and see how it behaves with your smolder material. Ask a local bee keeper what's the best smoke pot material in large quantities in your parts. You want something you can rake up easy and pile into construction sized garbage bags.
Then again, if the budget can afford it, the Tube does sound pretty convenient.
EDIT: You don't have to clamp the lids during use. They're heavy enough to stay on. With utility leather gloves the crews can pop off the lid and add pine needles or whatever you're using.
DOUBLE EDIT: I just took notice that you are in California. I'm guessing that your local fire people won't green light smoke pots.