yeah there have been a few Stigs.
Perry McCarthy was the first, and he outed himself as has been mentioned and got fired for his trouble.
Ben Collins is the current incumbent, but there have been guest Stigs too. Heike Kovalainen was a Stig at one point, I think for one of the bits that featured F1 cars, I'm pretty sure there have been others too... he seems to get taller and then shorter week to week lol.
Cojones of steel on the boy though.
I can't remember... did he ever drive that madness-on-wheels that fried Jason Plato, or was that just Clarkson?