I received a QSL from Caribbean Beacon, the broadcaster of the late Dr. Gene Scott. I made a few failed attempts at obtaining an IRC before deciding to include a U.S. dollar with the letter. The stamp shows a postage value of $1.50 but that could be in East Caribbean Dollars (XCD). If that is the currency used there, then they made a slight profit - XCD$1.50 is about USD$0.56.
My letter was mailed on September 6, 2006 and I received the card on February 20, 2007. The signature of the card includes an email address (see my photos linked below) so I wonder if they will send QSLs for emailed reception reports. It's worth a try!
Photos of the front and back of the QSL are linked from this page:
http://tinyurl.com/2xh6fx