Nowadays there are enough trade name laws that make it very difficult to get away with this. Most of these bogus attempts to rip off the actual makers name happened in the early part of the twentieth century. One example of an actual stencil is Steinvey, which looks almost like Steinway. Some piano dealers were that devious(and maybe some still are). Sometimes these names were misspellings of famous companies with the intentions of capitalizing on the famous name. A stencil piano is one made by various piano makers for companies or individuals who place or stencil their name on the front of the piano. We have also made an effort to avoid stencil piano names on this list. And keep in mind that while this list is quite long it still does not contain all piano brands that have been made since the history of the piano began around 1700. Most likely though at least 75% or more of these names will never be seen again on a piano. It's possible that in the future some will be used again. Many names are owned by various existing piano companies that are not currently (2012) using some of them on their instruments. Many piano company names on this list are no longer used and the makers in some cases have been out of business for years.
This listing contains hundreds of pianos in it's long history of manufacturing. There is also a huge number of piano brand names. This page contains a huge list of piano makers and manufacturers.