You are right about mottled colors being more common.

I am not interested in confirming who has what. Mannington does not make linoleum, but Armstrong states that they do. A quick look at Tarkett & Infinity shows they make linoleum.

http://www.armstrong.com/flooring/products/linoleum

http://www.tarkett-commercial.com/floors/site/en-us/ann/637/announce.asp

http://www.infinitycork.com/

I have the information that I need. If I can get a sample, I'll measure the thickness and report back here.