Microsoft Excel Wishlist: Please integrate with R

Further to previous post "Excel VBA – does it have a future?", a recent discussion about the future of Excel brought the participants to an interesting conclusion...

With the advent of the 1,048,576 by 16,384 grid and 64 bit Excel there is a capacity for Excel to work with very large datasets.
Why not take advantage of this and allow Excel to run natively as a client of a server-side or client-side implementation of the recently Microsoft acquired Revolution Analytics distribution of R?
Since Microsoft have done almost nothing with Excel VBA in the 21st Century, why not do something more interesting?  I am aware of various open source projects in this field but here I mean as a first class, OEM supported offering rather than an aftermarket enhancement.
See also