Wait, Hellebore Silver Dollar? I don't even remember, somewhere in Europe I think - remember this original article is OLD! Maybe Belgium? I used to know a source ... an expensive, foreign source.
The person who owns the plant whose picture I used lives overseas, and bought it at flea market or something for a few bucks (or whatever they used), but I think when I wrote the article it was available at some European nursery for a lot of $$$ - do you want me to try to find it for you? You probably couldn't even get it from Europe for a while due to the volcanic ash in the air space closing down all the airports.
Yikes! I guess I'll wait a few years. It seems Europe has all the best plants. So many times I'll search for a plant and most of the nurseries are in the UK.
I think I'll take a look at some silver-leaved at PineKnot.
I love hellebores. In Zone 7, where I am, there are few plants that are as noteworthy, and regal, in the depths of winter.
As for silver-leaved varieties, I've never grown any but see "plantdelights.com" has H. argentifolius "Silver Lace." Heronswood has H. foetidus "Frenchy," although the blooms don't seem to be impressive (existent?) so what's the point? (I have never ordered from either.)
Depending on what you're trying to achieve with gray foliage, you might consider the available varieties with "inky" flowers. Both sites have these.
I loved this article. My addition would be Golden Chalice vine, Solandra. I first saw this in Barbados and it did grow in my East and South windows (when I had them). Bloomed in winter indoors and the smell was wonderful!