Have you spoken to Colin Cambell? He might have some experience to help you.
http://www.campbellclassicmotorcycles.com.au/index.htm
In the UK we have Central Wheel who build up rims and spokes for pretty much anything. I managed to find some NOS Dream rims but have also had some successfully replated for about £70 each. Where possible, I have my original spokes replated with zinc and rebuild them myself.
http://www.central-wheel.co.uk/rims/rim ... edure.html
This is a pair of replated rims and spokes for my CB77 project. Total cost about £180.

Wheels Built by graham.curtis, on Flickr
Good luck
G