Is it possible to replicate the PHPFoxV3 Design Profile feature in V4?

Essentially in the old PHPFox V3 each user could actively edit the CSS on their profile page, which let them give visitors a unique experience. At the same time, a user could easily check a box reading “Hide Custom CSS” and be given the sitewide stylesheet. In PHPFox V4 they removed this feature during the full rebuild. I was wondering if this fix is as easy as it looks, i.e. creating a page to accept CSS code in a textbox, convert that to a [username].css file and loading it to a user’s specific page. The problem with that is, PHPFox tends to make nothing that simple, and will, in a sense, fight to force its settings. Anyone have experience?

Source: stackoverflow-php