I am going to be making my version of the Kate Sullivan / KoryAK gerbera cake for a bridal shower this weekend. I've seen several versions on here, but most of them are at least partially fondant - most are all fondant. I did find one that was all buttercream - I PM'ed that person, but she hasn't been able to get back to me. Here is her version in all buttercream :

http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1747324

My question - how do you think you would do the side designs in all buttercream? Paint them on (how do you do that)? Use the tip that's a smaller version of the giant icer tip (smooth line on one side, jagged on the other)? Any other ideas?

Kinda getting freaked out that I'm going to end up with a disaster on my hands.

Well, it looks as though it was all yellow first.
The yellow is patchy, so I'm guessing airbrush.
If you want the yellow even, just tint the buttercream before icing the cake.

Next the flowers look to have been painted with a paintbrush and gel coloring; then the flower outlines piped in white, the circles piped in yellow.

I would agree that the yellow was airbrushed on, since it isn't a even coat and the tops of the cakes are white. You can totally just ice the sides in yellow buttercream.

I agree with painting the flowers.

You could used thinned down buttercream and a paint brush.

You can use colored piping gel (color it white first then the color so it isn't as transparent) and a paint brush.

You could use airbrush colors or thinned down color gel and a paint brush.

I agree with doing the painting first then outlining in white.

What exactly is piping gel? Is it something I can make?

I don't have an airbrush, so that's out.

If I go with the thinned buttercream . . . how thin do I have to make it? I use Indydebi's buttercream recipe - I'm afraid that I will just jab holes in the base icing.

http://cakecentral.com/recipes/7348/piping-gel-recipe
http://cakecentral.com/articles/103/stained-glass-effect-with-piping-gel

Wilton makes piping gel. I want to say I have heard of recipes for it but I have never made it myself, have just always used premade.

You can use airbrush colors with out a paint brush so you don't have to have one for them.

As far as thinning down buttercream, you'd just want to thin it down enough to be able to paint with it. I can't really say how thin that is, probably something you will have to go by feel for.

What I would do is spread a little buttercream out on a piece of wax paper and try out the different things and see which is easiest and which you like the looks of.

The skate board in my photos was buttercream and I used a paint brush and airbrush colors on it. You can paint on buttercream, you just have to have a light touch and a soft brush.

I would just airbrush the whole thing. Using the sheen airbrush colors for the flower design on the side.

I think you could fill in the flowers with colored buttercream that is not mixed well so it is mingled in color, using a tip 3. Then smooth it immediately with your finger dipped in cornstarch before it crusts so it doesn't leave lines from the tip you piped with. Just an option?

It looks like for the yellow you could use a damp paper towel (probably viva) dipped in some very thinned out or watered down golden yellow or buttercup yellow gel and sponge it on like a wall treatment.