never seen a CAD of one but your dims sound good, maybe go a cm or two wider if you are 80kg or more.
Make the nose round, wide point about 2/3 forward, parallel rails, wing it.
Some have the wide point even farther forward, for kiting there is no reason for this imho.
I did find the link to the waterlust alaia building guide pdf, looks like there is a cad file link too:http://www.waterlust.org/woodsled/
About rocker, they suggest using planks that have a little natural curve to them, easier than bending or carving, if you can find planks with a small, similar curve...