I've looked before at mobile aware style sheets for the software this forum uses (for other projects). They are either really crap, or really complicated to set-up with big design implications for other parts of the site.
It would be do-able, and I guess that better solutions now exist (it has been a year since I last looked) - but at the moment not something probably worth perusing.
Although, I do understand the benefit. I regularly post from my phone, and it would be nice to have a better mobile interface. Sometimes the download times and zooming are just that little bit annoying.