There's a pretty big difference between Hitmen and Hatchetmen... and I wasn't talking about ISTPs at all (although that's a good match). Hitmen are hired and take out people the client doesn't like. A 'hatchetman' is a guy who does the jobs that nobody wants to because their conscience says 'no' -- as in laying off people, dumping nuclear waste into unpolluted streams, stealing candy from small children, etc.
I believe you're looking for 'Absentminded Professor'?INTP - The Uneasy Scientist? The Moderatly Displeased Scientist?