Evergreen plastics

1. Yes. They are pretty good. I use their sheets and shapes on various projects.
2. I don't have any photo's but, here is the link to their website. No pictures here either but, you can get an idea of what they have to offer.
http://www.evergreenscalemodels.com/index.html
Here is another company that has plastic sheets and shapes.
http://www.plastruct.com/

I've used them, good for scratch building.

Use it all the time, great stuff. Comes in a multitude of sizes, strips and sheets, as well as clear sheets. I get mine through Greatmodels.com.

I pick up the mixed bags at my LHS. $5 and you get a bag full of everything almost! Pretty useful. Then you can just buy 1 or 2 pieces of what you know you will need.