Gotta say I never had any issues when I had them on mavic cd's and hope hubs.vertical strength is very strong if the person building them does it right.saying that paul at bike shack in York always did build a strong wheel.
And cheap wheel builders tend to be cheap for a reason.
I'd be finding the best wheel builder i could for something like that and hang the cost.
(Actually, I wouldn't even get a build like that, but I'm sure you know what I mean)