It has been mentioned before here that real linen has better abrasive qualities than cotton or hemp which are used nowadays for strops.
That is why I have been looking for a source. Hard to find as real linen is mainly used for luxury tablecloths and bathroom linens.

Bu I did come across this: http://www.woodedhamlet.com/beltings...inen_webs.html

The second one is described as 100% linen girth webbing available in 3" width.

I have sent them a fax for a small sample but got no reply. Does anyone know this place or even the product? Would it be any good?