Big Agness offers a Merino (87% New Zealand Merino wool, 13% nylon) sleeping bag liner that can be used as a stand alone for warmer conditions. At 82″ long, it features 60″ of girth at the shoulder with a snap closure 42″ side opening. The neck opening incorporates a shock cord closure.
www.bigagnes.com/Sleeping-Bag-Liner-Wool
I like this, for someone who prefers synthetic bags this is a nice mix and match