I must say thank you for all of your great suggestions for a headboard when I wrote about Robert's new room here.
One suggestion was to:

I like the idea of adding natural wood to his room for character and warmth. Perhaps something like this DIY headboard from House*Tweaking which happens to have my favourite word written on it:

Or I can imagine a row of hanging buntings painted in white on the wood would look great too.
(Bottom image House*Tweaking found via The Happy Home)