Is there a way to stencil on the side of fondant covered cake w/o using RI? Is there some way I can use Wilton icing color thinned w/ something? Will it run down the side? Help and thanks!

Do you have an airbrush? That would be the next logical thing. If not, you could try Wilton color mist.

I have stenciled using the Wilton colored icings right out of the tubes; works great!

You could add a little food coloring paste to piping gel.

food markers