I can't seem to find my rose tip and I really want to do a ruffled cake for a friends birthday tomorrow. Is it possible to cut the right shape in a parchment cone to get a similar look?

How about a leaf tip?

I am not sure, but if you have not other choice give it a shot, you have nothing to loose

I can't find a leaf either; basically all I have available is star and round. I almost never do buttercream cakes so my tips have been gathering dust for 5+ years. The parchment didn't quite work; I think the fact that I'm actually using whipped cream, not buttercream on an ice cream help didn't work in my favor! I ended up doing a petal cake (sort like this, but softer: http://www.thecakeblog.com/2011/04/diy-vintage-petal-cake.html) and so far it's lovely

It won't be ruffled but, try the star, it might be interesting.