30 mins

Edit: I added a second image I did following the same timing constrictions

So this is the result when I actually time myself for a speed-paint. I gave myself 30 minutes, and when the clock rang, I dropped the stylus.

Not a bad start I suppose. And just in case you're wondering, the portrait "series" is still happening, I've got two more on the works now, so look forward to those [=