I haven't read everything again on this post. Sorry if I'm giving a bad type of info or repeating someone else saying.
However, I have seen Grae talking about diesel and alcohol and that interested me: it can't work. However, diesel engine were designed for heavy oil and they would work on any type of oil (from arachid to olive). You can put about 50% of vegetable oil in any diesel engine and 100% if you can attached some eating device on it.
About Gazogene, the last info I had is that are used again. Older model type are still workable and they would use coal, wood, or anything that can burnt. However, you need some time to start the engine. Newer models are fun so; they use specific type of wood and are more expensive to run than gas vehicles.
Nice point about Methane, every town and city could burry their trashes and get some.