Can I take a butter cream iced cake and cover the whole thing with fondant stripes?

Yes, I do it all the time. You just have to be more careful of marring the surface of the buttercream. I use stripes over SMBC.

just did it with my circus cake!

I have also done this, worked great!

I just did it on a topsy turvy cake with italian buttercream. I didn't completely cover it, but it can be done.

this picture is in my gallery already.

The answer is yes, yes, yes! I have found that adding fondant strips to chilled BC cakes limits "smushing" or messing up the surface of the BC cake. I have several cakes that I've added fondant strips or decorations on BC cakes. HTH

Sure! All the cakes in my gallery are buttercream with either fondant or marzipan accents.