Thanks for all that. Very informative. Like all of us I guess, I've popped a few spokes over the years on ordinary bikes doing not very extraordinary things. I remember reading once, and I can't remember where that if you've travelled 1000k on your bike, each individual spoke has tensioned from nearly zero to its full front or rear load a million times. From that day on I assumed that more spokes would be better to spread the loads - didn't think of the other ways there might be to build rigidity and strength into the wheel - as you've described.

Good tip about velocity rims - they're made here in oz (by an ex-pat citizen of the USA) - my LBS owner also raves about them.