I have an insulated stainless container from OXO, I believe. It fits and stays in a bottle cage, has a solidly-sealing sipping opening and keeps my 12 oz Americano comfortably warm after a 40 minute ride at 35 degrees.
I purchased it at a discount store for less than $10US.
http://www.oxo.com/xxoxo_ibeCCtpOXOP...7rtGa%253AS%7E