Does such a beast exist? I know there are those who will say to own more than one main bike (ie as opposed to the winter hack which gets used when the weather's shite) but for some of us that idea wouldn't be condusive to domestic harmony

The 11S I would imagine could come high on a list of possible 'do it all' bikes. I'm not just talking tangibles either - it has a very important factor for me in that it has real character. It'll also do track days, or take 2 people with plenty of luggage across the Continent in reasonable comfort.
This is what I feel is a shame with the new S, in that a lot of the old bike's skills will have been diluted to the point of non-existence. Sure, BMW may have been trying to go for the sportsbike jugular but it does seem a somewhat half-hearted attempt - and someone who wants to buy a 999 or Mille probably wouldn't look twice at a shaft-driven, air-cooled Boxer twin. The ST may be a good alternative for the 1100S owner looking to go to a more modern Boxer but sorry, with a bike which looks so hideous even its mother wouldn't love it, I just could never give one garage room. Shame as I feel the idea is a sound one, only poorly executed. It may or may not be good to ride (I've yet to have a go on one so won't pass judgement based on lack of experience) but as is often the case with BMW it seems like an opportunity missed.
Is there anything in the current BMW range which could replace the 1100S - and still be as useful a tool, and look as good? I really don't think so which in many ways is a shame.