I've been thinking about it...
... But IPB 4.0 is due out very soon (or so I'm led to believe).
And when that comes out the site will be fully responsive, so there will be no such thing as a mobile version of the site, don't want to waste time creating a yellow and green mobile skin if it becomes redundant soon after.
I could probably just install an off the shelf skin which isn't blue, say a white one, and then stick a NorwichTalk logo at the top - would that do?