We're wondering if anyone has seen a fastener like these.

Quite often... on Ikea furniture, actually.

That type of fastener is called Dzus fastener and they are widely used in aircraft race cars etc etc..
http://www.southco.com/browse/dzus-quarter-turn-fasteners-7345.html

They are known as "Dzus" (pronounced "Zeus") fasteners, and are quite common on aircraft, and racing vehicles.

See http://en.wikipedia.org/wiki/Dzus_fastener and http://www.southco.com/searchresults.aspx?query=dzus

Jeff

Also very common on classic British & European sports cars.

As Gary mentioned, they are used in auto racing a lot. I have used them from holding body panels on to holding the nose and splitter of a race car on. Once they are set up right, they have a good grip and normally stay locked.

If you are looking for some, try a hot rod place like Jeg's or Summit Racing. Moroso makes some and you can look on their site to see the different grip ranges, very important depending on what you are doing.

Try doing an internet search on "Aircraft Spruce & Supply". This is an outfit that sells all sorts of stuff for people who build their own airplanes.

From my experience of building racing cars in an earlier incarnation, they're much cheaper to buy from aircraft component suppliers than motor sport-oriented shops.
Cheers, Bob

Hi

You can also look here.

http://www.dfcis.com/index.html

The size is most likely stamped on the head.

Tim