I was thinking that to myself this evening in the freezing cold, as a scraped congealed veg off the floor of my outbuilding in an attempt to get it a bit cleaner. Winter fuel making requires some proper grafting - something the vast majority of the population just wouldn't be motivated to get on with.
Despite the cold and the unpleasantness, I felt a sense of pride in our little community. 
If you got your arse in gear and built the 500 litre one you wouldnt have to spend as many nights brewing 
Tell me about it, I'm in the process of clearing an area of the outbuilding so I can work on it inside in the winter, though it's slow going. I've bought some mighty steel warehouse shelving, so I can get all my junk arranged vertically rather than horizontally

Part of the reason for scraping the floor clean in the processor area is that I don't want any stray welding sparks to set fire to oil-soaked sawdust. A bit of oil on a concrete floor would probably be OK though. Anyway, that's the other side of my concrete bund right at the other end of the building, I'm probably just being paranoid.
I also worry in summer with sawdust down, about spontaneous combustion due to oxidisation. I can't help feeling that sawdust is a bad plan all round and nice easy to remove cardboard is the way to go!