I am trying to make a cake topper. I plan to cut out a large flower (simple wilton cutter) from gumpaste, and then adhere '16' to the flower for the cake. I want the plaque to stand up on top of the cake. I know that I will need to attach wire or something. Looking for any advice or a tutorial to help me do this successfully. Or, would it be better to cover a piece of cardboard/foamboard with gumpaste? Not sure how to hide a seam if I go this route. Here is an example cake: You will see that I asked the decorator how they achieved this look.
http://cakecentral.com/gallery/2230642/university-of-kentucky-uk-birthday-cake

I plan to , and then adhere '16' to the flower for the cake. I want the plaque to stand up on top of the cake. I know that I will need to attach wire or something.

cut out a large flower (simple wilton cutter) from gumpaste
Lat the flower face down and while it's drying lay 2 dowels (seperated a bit) that extend beyond the bottom of the flower.Use gumpaste 'straps (small strips) to adhere the dowels to the back of the flower. Once the face dries, lay on your nimbers to the front of the face.
Let dry completely. Stick dowels into cake top.
That's how I would do it.

If you have tongue depressers or ice cream sticks, they work great. That is what I use for my flat toppers. The flat side of the sticks give you more surface to adhere to than a dowel will. However, a dowel will work.

oooh yes, we have tons of popsicle sticks! Thanks both of you!