One point I learned from this very inspiring discussion is that we should distinguish a little between dieselpunk in literature and film, and dieselpunk as a lifestyle. In books and movies, some degree of fantasy and/or sci-fi is obviously required to separate dieselpunk from historical fiction. As a lifestyle, dieselpunk means to integrate style elements from the Diesel era into your everyday life. This could be music, fashion, art-deco pieces, etc. Different from nostalgic people, dieselpunks do not dream of having lived in the past. Dieselpunks have also not the intention of being historically correct. While there is no official definion of what a 'punk' is, one common characteristic of punks might be some lack of respect. Dieselpunks show this lack of respect by the reckless mixing of style elements of different eras. Sometimes, there is even a lack of respect for political correctness, e.g., by wearing insignia or uniform parts of 'bad people'. In particular in Germany, this has already provoked some anti-dieselpunk arguments, since some outfits to be seen on WGT aroused suspicion that dieselpunks might be part of the extreme right movement.
Let me add my two cents on something. Decopunk, Dieselpulp, Dieselfunk, etc.... they're all Dieselpunk.
Joern, in my opinion, we don't need different definitions to differentiate between dieselpunk in cinema and lifestyle. Using enough sense to not wear clothing that makes you resemble a neo-Nazi is the solution. It's like having enough sense not to walk around dressed like a member of the KKK here in the States even if you thought that wearing a robe and dunce hat looked cool.
All we need is one good definition that covers both cinema and lifestyle, which we already have in the classic definition. Multiple definitions confuses the matter, which I believe the proposal that dieselpunk is nothing but science fiction does.
Alright folks, here's my blog post on the subject. "Your Dieselpunk is Too Small"
I made it easy on myself when I sorted the dvd-collection into categories a few years back. Anything that is dieselpunk, pulp, source material and the like, 'just' wound up in the Pulp category.
Star Wars is in the Science-Fiction section though. ;)
Answer to the 1st question: No
It's difficult enough to explain the idea behind dieselpunk to outsiders. More terms and definitons would just add confusion.
Answer to 2nd question: Yes
I'm quite sure there are dieselpunks collecting stuff made in the Diesel Era. A lot of photos published in this forum do also shows real things from that era.
Scientific and technological development can be quite rapid. Less so with the fantastical. Are 1930s vampires really so different from 1890s vampires?
So what characterizes diesel era fantasy?