You could try using CANalyzer, it is a program capable of many of the things you need, including busload calculation, and advanced programming of scripts and displays. They also have an optional package that lets you tie Labview and DIADem into them.
take a look at their website for details.
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The bad news:
Right now, CANalyzer only works with Vector CANcards, it WILL NOT work with NI CANcards.
Hopefully you are sitting down when you look at Vector's pricelist, their prices are shockingly high.
Other than that, I would suggest writing your own.
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