I've done it, but never with 'repaired' cymbals. I just took a thin top and a heavy bottom, and have gone as big as 18". It's fun for a visual lark, but not practical. The hi-hat stand has to move that much further away from you, and they do sound pretty 'washy'. But it is cool to do once in a while, and get a few weird looks, especially from other drummers.
You want to really mess up other drummers? Go out there with an 18" kick (or I've turned a 16" floor tom on its side), a 10" rack tom, a 14" floor tom, and a 12" snare. Now add a 24" ride, some 18" 'hats', and a 20" crash. Yeah, I mix my meds sometimes.