Start saving your cardboard boxes! I bought a dragon hat from Aberdare Party supplies last year....my face shows in the dragon's mouth like it's eating me....well worth the £7.99!
Not exactly egg cartons etc, but how about this one?http://www.hitentertainment.com/artattack/dragon.html
And here's one with egg cartons, though not a Welsh dragon, but a Chinese one... Maybe you can adapt the design.http://www.activityvillage.co.uk/egg_box_chinese_dragon.htm
Come on readers show me some bloggy love!!!