I feel I need to have some input in this but I cannot contribute massively due to the lack of free time and whatnot but I don't mind doing bit's and pieces or give advice. I remember vaguely bringing this up when I first joined too.
I have heavily modified vBulletin 4 within my own website and I have dabbled with vB3.
Graphics for the UI are no problem, plus I'm fluent in PHP, CSS3 and HTML 5 and intermediate with Javascript.
In my opinion I would sack off designing for mobile. I have managed to use these styles on my iPhone without any problems and just think it will be effort worth using on graphics and integration.
For us to design a theme for vB3, we will need a copy of it. How else can we get the hooks, vB "if else" statements, and other behind the scenes code without Admin giving us all access to the Admin CP?
As for design wise, my idea would be to replicate a place from any Oddworld game without just slapping a screenshot in as a banner with "Oddworld Forums" on it.
I will elaborate once I have heard others thoughts
, nice to see you all again by the way.