Cotlin is probably your best bet: nice yarn, well-priced.
I used Rowan Linen Drape, which has some viscose in it. It was being discontinued but I found a bale of it cheap on eBay, in gorgeous colors, so I grabbed it.
I think the nicest pure linen yarn is Euroflax. It's pretty stiff but softens with washingg; some people wash it before knitting.I think the Mason-Dixon book has some patterns for lacy washcloths that use it. The downside: it is very pricey.
I haven't tried this blend, but it's tempting.