A smarter way is simply to buy a new spoked rim with hub dynamo already built-in at the annual sales when the old one wears out. You just need to know which annual sales.
Last time I got a hub dynamo a ready built wheel from my LBS with a DH3N72 was cheaper than buying the hub alone. Rim was a fairly wide Alex model, perhaps not the best but sufficient for the use on one of my visitor bikes. LBS sourced the wheel from Germany.
I want to go with a ready build BUT must have grizzly rigida rims not prepared to compromise on the rims. Is it possible I could get a ready build with them?
That's likely to be an expensive barrier because what we're talking about in these sales are the surplus wheels of the mid-level mass-market assemblers. Some of the really top baukasten (semi-custom houses) may have Grizzly rims as an option, but they're not the people who sell off surplus wheels.
My own opinion after much expensive experience is that if you've decided on a certain component as non-negotiable, any lesser component will never satisfy -- and you end up buying twice or becoming bitter because the particular component you were convinced is better than anything else in that line has gone out of production in the meantime. (I especially suspect the Germans of withdrawing really good bicycle components and replacing them with "improved" versions that are simply ruined, merely to irritate me.)
On the other hand, I learned about wheel building by fixing wheels that came from Gazelle in a deplorable state on one of their premium bikes and needed attention so often that my riding companions got used to me taking out the nipple spanner at almost every rest stop. Whereas a set of wheels I have that Keith Bontrager built for a prototype Trek have never had a spanner on them despite considerable abuse, and a set of wheels built by Utopia, which I ride at speed through potholes that would swallow a smaller bike, are in their tenth year without a spanner on them, drum-tight and perfectly round. (Short version in previous post by Anto...) Good wheels are built by known-good people. Cheap wheels off the internet may be good, or they may have been built by the all-thumbs hungover clown who built the wheels on my Gazelle; you proceed on the perfectly safe assumption that the majority of the wheels put on the market by reputable manufacturers will be good. This kind of bargain is further improved, or made at all possible, by the tacit assumption on this forum that, if you get unlucky, you know how to fix a wheel that isn't blueprinted, or that you will ask for the advice generously available.
If you're going to order wheels built by SJS, as Martin suggests, it might be well to do it sooner rather than later, so as not to get caught up in the Christmas queue*. I seem to remember that Dave from the Workshop mentioned last year or the year before that the orders pick up around Christmas.
*For our American friends, a queue is British English for a waiting line, not a bullfighter's badge of office.
