I honestly wouldn't try it....it would lose alot of the smooth draped look...
I suppose its *possible* with a nice shiny noncrusting buttercream if you had the right tip and a very steady hand...but yet still it would be lacking a depth that the fondant has.
I wouldn't do it with buttercream no matter if you made it a little stiff. That design is better done in fondant.
I agree w/the others. I'm a b'cream gal and I don't think one could come close to the proper look w/bc.
Why don't you do a practice run on a dummy? - even a small 6"er