I came across a site recently while looking for the same thing,http://www.hamstuff.com/QslKitPage/qslkit.html
It is a simple kit of micro perf paper with 4 cards per page. This is marketed toward inkjet printers. They throw in a MS Publisher and Word format files along with some images. The 100 Sheet order (400 cards)of 90# card stock is $13 plus $4.50 shipping. At less than $20 shipped I plan on ordering one myself so I can do some custom cards.
Hope this is useful,