I tried this recipe tonight...whipped cream folded into sweetened cream cheese. I loved it.
http://www.cakecentral.com/cake_recipe-901-25-Whipped-Cream-Frosting.html

I want to use it on a 2 tiered white cake this weekend. Will it hold for borders and side decorating? I want to attempt this desgin. What do you think...will it be stable enough? Thanks!
http://www.cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1254080

Has anyone used this icing before? Is it stable?

Well, it certainly won't be stable outside refrigeration.

I would think that as long as you weren't planning on letting it set out for several hours it should be fine. That is one thing I have not tried, though I do tend to mix most of my frostings and fillings with whipped cream, it always turns out great!