So far in my search I haven't found a local resource that operates anything like this,,,,,yet. I'm sure they're out there, but I haven't found them yet.
I would call each company that you are considering and ask for for a list of customers that have bought one near you. Then do some visits. If there isn't anybody close, then some road trips would be worthwhile. Heck, if I knew of someone near me with one of these machines, I would want to go watch it work because of my curious nature. I love new ideas and approaches, and since I am a do-it yourself type, these things interest me for future refereces. The lack of them out there(that I've seen) makes me skeptical.
Our lake is about 3.5 AC and I've got about 1' of muck in the places I've measured it. That's about 150,000 cu ft of muck. I agree that it is going to be hard work but my plan would be to nibble away at it over time. Right now I'm not looking at doing a drain and scoop method and instead want to pursue a lower impact method of cleaning it out. Once it's done, I'd be looking to sell off the "gently used" equipment.
1' of muck doesn't seem like much. Have you considered aeration to minimize the muck? I agree that a dragline would be overkill for only 1'.
A dragline isn't good for light material like muck because muck almost immediately liquifies once it is scooped up. That action would stir up all of the trapped nutrients into the water column instead of removing them, which is the intention.
Just guessing on this, but from the videos, it looks like they "isolate" the area off they are working, so this process might also stir everything up.
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With my experiences so far with pumps, I would be cautious of how much the pick-up line gets plugged. They seem too, even with a biggere hose it just means larger/longer objects stick on the end and then starts to accumulate more and more stuff. Then you would be cleaning the end frequently. It would depends on what your muck is made up of. If there are tress nearby, you can be assured there are sticks, etc
Also, what about the accesories that you might need? These could add up fast. Those dumping areas/bags might be costly.
