The key from a Bentley will work with a Golf with a little bit of modification (and it's a nice key).
I imagine one could probably set up a Veyron key to work with a Golf...
Indicator stalks as has been mentioned is a £4.5k part milled out of magnesium as I recall.
The W16 engine is 2x W8 engines... and the W8 engine is based on a VR4 (so an .:R block with two fewer cylinders). However for the Veyron I imagine all the parts of made to a significantly higher tolerance than for the Golf equivalent... probably bits would fit though.