re Vne, I was always told it is much better to exceed Vne in a straight dive than pull hard on the controls to avoid the overspeed. At Vne you are already some way above Vmo so the likelyhood of something falling off when you pull hard on the stick is much higher.
I find that interesting - I've been taught exactly the opposite:
I am given to understand that under JAR regs (and I suspect this will vary by aircraft category), the aircraft has to withstand a 50% overstress in G-loading for 30 sec, and still fly (you may not be able to re-use the airframe, and it may completely expire at 31 sec). The testing for velocity requires that the aircraft is flown to the maximum design dive speed, and Vne is set 10% lower.
Therefore you have (loosely speaking) a 10% margin on Vne, and a 50% margin on G. I'm also told that flutter is the likely limitation beyond Vne, and onset is rapid, and rapidly destructive. Obviously this is likely to be somewhat airframe dependant.
I'm also interested regarding V*m*o - I presume that's more applicable for a/c that also have mach limitations / Mmo - it's not a number I've ever found defined for anything I've flown.