I'm having my original (as far as I know) back wheel rebuilt by a local specialist. He says the rim is useable with a bit of reconditioning, and he's going to vapour blast and skim the hub, reline the shoes and rebuild with stainless spokes.
If all goes well he can do the front as well; although it's not as bad, it was rebuilt with an MZ rim many years ago when the bike was written off.
I'll post the results, prices and contact details when I get the wheel back in a few weeks.