Check out the wheels on the stakesy's website, probably a good start and add some stiffening then probably half decent.
The frame needs to be stiff to apply constant pressure to work properly and it's this contact pressure that creates the shape. The old cast iron ones I've used are still pretty stiff. They are obviously very heavy and the mass stops them moving about unlike lighter steel frame wheels.
A Lazze copy wheeling machine would also probably be a good start, I've seen them for sale in Europe but don't know of anyone that sells them here.
Found a Laze copy: http://www.ebay.co.uk/itm/WNS-Profe...d=100011&prg=9537&rk=3&rkt=10&sd=261255597871
been looking at that one didn't realise it was a Lazze copy , pricy though