Personally, I probably would have gone after the BMW drivetrain, simply to be a partner with BMW, instead of the tag-along on the McLaren-Mercedes/Force India partnership, especially with VJM having some say over my operation...
And I think we will see this new sponsor being Microsoft. The colors line up, and realistically, they are sitting on a $55B "war chest", so they could effectively under the new rules coming up pledge $10B to the team over the next 20 years!
Or maybe it is just another wet dream?