In the MRO business those are technically called "E" clips. I have a very well stocked shop and may have what you need. Can you measure the pin diameter.
Or for those who prefer to shop on their own
http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=2004&PMCTLG=00
Take it from someone who shops online most of the day...they don't take six months to find.
