I was surpised there were that many. Silver Streak had a pretty long run fron 48-97 but they only built about 5 trailers a WEEK. Streamliner went under in a sell off after a buy out in 74. After looking a little on this site http://www.tompatterson.com/Trailers/Trailers0.html
both compaines had simular goals at to produce quality as Airstream. To be quite honest it appears both were modeled after Airstream in both product and organazation.
That site is about the only refference I could find to the Countess. It's easy to see why this Lobo thought he had a Airstreambecause they have a simular appearence. Really is a rare old camper he has. It was one of the last products they ever built.
Streamliner had a club very much like WBCCI called the "Royal Rovers". Still existes but is very small now and pretty well the TX chapter is the only one left. Silver Streak also had such a club that still exists but due to their low volume not many members.
Lobo looks like you have a Orphan trailer for Streamliner. Hit that site it has some interesting information and pictures are availabl of the products. They also have some Airstream info there and a classified area.
If I'm slow tomorrow I'll look up some of those other marks and see what I find Wayne.
Thinking back to when I was a kid I seem to recal a neighbor have a trailer that must have been a Streamliner. I remeber the Gold crown on the side and stripe down the side.