"Darby and Joan"

I used this phrase in American company the other day and came up with a blank. Is it only a U.K. origin thing? This webpage seems to indicate so.

For any who don't know this phrase, it means a devoted old couple leading a contented, if a somewhat boring life.

Taken 10 years ago. A long way from being
"Darby and Joan" yet.

Generally I've heard it used in a slightly negative, yet perhaps nostalgic fashion about oneself. "Ah, look at us, Darby and Joan." According to Wikipedia, Ruth Rendell wrote this in The Best Man to Die (1981), "My father called my mother darling once or twice and there was a kind of Darby and Joan air about them." I found a lovely blog post by an Australian here, using the phrase in the way I'd use it (it also includes the words of a song called "Darby and Joan".

As I looked it up online, I was surprised at how many literary and musical references there are. Here are some other uses of the phrase:

• There is a website of this name: http://www.darbyandjoanvintage.co.uk/ It's devoted to vintage china and accessories.
• And the Darby and Joan organisation: http://www.darbyandjoan.org Established more than 60 years ago. They care for elderly in their district in England.
• Darby and Joan Ltd. is on Facebook. They are event (presumably vintage events) planners in Derbyshire.
• A painting by an Australian in the 1800s is called Darby and Joan. 
• Would you believe I found a Darby and Joan Cabernet and Chardonnay from Australia.
• And finally, a quaint video clip about the opening of the Darby and Joan club in 1942 in Streatham, London.

So, tell us, where has this phrase ended up? Have some Americans heard of it?