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My 2006 330i (N52) does the same, as does our 235i (N55) occasionally. Despite these engines being exceptionally smooth, once they're all loaded down with the accessory systems going, there's little that can be done to smooth them out, apart from increasing the idle.
As you add more and more load to an idling engine, at some point it requires more and more "idle torque" and since we're talking idle speeds, each combustion event is spaced out pretty far (time wise), and each needs to be pretty strong to keep the engine running under high load... this of course translates into vibration. Just the radiator fan pulls enough power to put a load on the engine via the alternator, now imagine all of the car's systems going.
It's offputting yes, but the engine mounts are somewhat squishy as it is, imagine how soggy everything would be if they made the mounts even softer to reduce NVH- then you'd have customers complaining about how soggy the drivetrain is on their $50,000 performance-oriented BMW. Everything is a tradeoff, including raising idle speed.
And about raising idle speed- I am not familiar with the modern BMW DME's, but just adding 50-100 rpm to your hot idle should help quite a bit, if that is possible, and if you're even willing to start modifying the DME of a car under warranty.
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