I found this recipe for Sturdy Whipped Cream Frosting. I made a cake with it once and we really enjoyed it. The frosting held up for at least 24 hours (in the refrigerator). I don't have any more stability data because the sample was, er, consumed in testing, but it was showing no signs of collapsing, softening, or sliding off the cake. I liked the frosting so much that I used it to make another cake yesterday. This time we had a larger group of taste-testers, and everyone enjoyed the frosting.
Cream cheese is used to stabilize the whipped cream, and at first the frosting has some of that tanginess of cream cheese. Since I had strawberries in the cake, the tanginess was a good complement. After about 24 hours, the tanginess had faded and was fairly mild.
This frosting has become my new favorite. It not only works for me, but I'm so jazzed that I had to share it (again) with you!