Has anyone tried a caked like this?  I can't tell whether it's buttercream or fondant?

I haven't tried it myself but it looks like fondant to me. I found this tutorial which isn't exactly the same but looks like a similar concept. 

http://rosebakes.com/pink-ruffles-cake-with-a-blue-bow/

Yes, I too think it's fondant.  But what the heck are all those hair lines at the base?

Some cakes are so close to the line, it's hard to tell, but I believe that cake is buttercream by a skilled operator, done with a tip.