I have heard that there was again a manufacturer of battleship linoleum in the US. For many years, the major sorces of real linoleum were in Britain.
There are 2 ways to find a source for this. The first is to go to the most well known and expensive flooring dealer in your area. Since they know that they can, in effect, charge for their knowledge and research, they will find a source.
The other way to find a source is to go to the oldest, shabbiest flooring dealer that you can find in your area. This generally involves visiting areas where there have been recent murders. The employees will be sitting around drinking coffee. Tell them what you want and they will either go in the back and bring it out for you or tell you who has it. This will be the store where they forgot more than what the first kind of store people will ever learn.