"I'm with you dear Marmie, I like to put on a show. So sometimes, on Sunday morning, at the Famers' Market I get the kids' makeup artist to put makeup on my face.
It does get me more attention, and it gives me the role of a clown (and by the way, my clown name is Minsky). The makeup allows me to do all the silly things I think of but am usually too sensible to do.
Would you care to stroll through the Farmers' Market with Minsky on Sunday morning, dear Marmie? How would you feel?"
I can't think of any examples of ISTP 5s, but I've seen plenty of ISTP 3s (though I don't know their names). most ISTPs are far to "come on let's DO something" to be a 5 who's natural tendency is to sit and analyze all day, that's more like an INTP
My ISTP brother I think is a 5. Introversion/Extraversion plays a big role here; there's a big, big difference in the temperament of an ISTP and an ESTP. Remember, both ISTPs and INTPs have dominant Ti.