might want to change to rubber tires for a smoother ride?
not original period look, but might work.

we have had discussions here about VARDO

these are beautiful, enticing, enchanting rigs!

here are a few links...may not be wheel wrights..

http://www.enslin.com/rae/gypsy/wagon.htm

http://www.gypsyvans.com/

http://www.speedace.info/gypsy_caravan.htm

http://gypsywaggons.co.uk/

http://caravans.oros.org/Caravan/Gypsy_Caravan.html

good luck and let us know what you find!