Ken,
I've ridden old and new campy, old dura ace, and sugino 75 and frankly couldn't tell much difference between them. They are all nice and stiff, and pretty. I recently had a Kalavinka built and went with the new dura ace cranks and splined bb, and they feel great, noticeably stiffer(for me at least). I'm also about the same weight as you. I have splined bottom brackets on my road bike(shimano) as well as my mountain bike(race face isis) and have had no problems with any of them. So, basically I don't think you should worry about the durability of the splined system.
Have you considered a new frameset? Possibly custom? There's nothing at all wrong with a pista, but it seems like you're serious enough about cycling to justify it. I've been riding for work and pleasure and competion for quite some time, and have owned all sorts of bicycles, some that fit well, some that didn't. But nothing I've ever owned has felt as perfect as this Kalavinka, it's unreal how good it feels. Sorry to derail the thread and spend more of your money, but I think you should consider it.
Eric