Hello,I have been selectively collecting Rueven or Reuven Glass -aka- Nouveau Art Glass Company since the early 1970s and you are correct, it is very hard to obtain any useful information about this concern. I know they are located in eastern Pennsylvania, near the city of Philadelphia, for whatever that is worth.
The piece in the first link is the only one you have which comes close to looking like their product. It is the distribution and over lapping of the colors and how they cover the entire surface of the item.
The similar type of glass from Israel, by the Ilanit glass decorating company and a few others; more often have a white or pale colored background with spaced darker colored areas, which are even darker in color along the edges.
Here is the rest I have managed to eke out about the Nouveau Art Glass Company over the years.
The main reason for the two spellings
Rueven - Reuven was the label maker's fault and nobody caught it for a few years, so there are many items out there with one or the other spelling of the name on their labels, which is why you have to Google & Ebay search by both names to see everything.
http://tinypic.com/in5q2w.jpgThe correct spelling is
Rueven and for awhile there was a website at
http://www.decora.net/rueven/ but it disappeared a few months ago.
Rueven doesn't make any glass of course, they do the surface treatment\decoration on it only. They purchase clear glass blanks from glass makers like
Arc International\Crystal d'Arques\Luminarc...,
Indiana Glass and a few others. I have a half dozen
Fenton animals they did back in the mid 1970s, which have the Fenton logo on them. I can only assume they quit using Fenton blanks, since I have never seen any more Fenton glass nor any animals offered in their line since the time I got mine.
The first lines of Rueven glass was decorated with the color mauve being the dominating color on the pieces. In the late 1980s they changed from mauve to a rose pink shade and in the 1990s they began doing items with green or yellow as the dominating color. All of these items come in a matte\frosted finish or a satin finish, which is like the other except it still have a bit of a shine to it, just like satin cloth does.
Later they began doing the color decorations on clear, natural glossy glass, plus they also did a treatment using stencils for the decorated areas on plain clear glass item.
There is a good size club\group of quiet collectors, with a private website, who are only after specific items, which weren't offered for very long and those pieces done in the satin finish are among the most sought after. The reason I say "quiet collectors" is because it is their goal to build their collections anonymously without driving up the prices.
Long post I know, with little useful information, but some information is better than none and in a case like this it takes a good bit of explaining.
MikeEdited to add: I added the bad link just in case they are only having computer problems and will get around to making it work again.