There are high side switches with current sense, e.g. VN5025AJ. Matter of fact, that might be the slam-dunk part you were looking for.
Ed: oh, down to 0.1V? Well, you can always power the "-V" from -5V, say. Which would screw with your logic levels, but that's not terrifying (use a single BJT or FET to invert +3.3 or 5V logic to -V).
If you're also wanting to do that with existing parts, you'll have to tell us what all you have / have access to, and how big you were expecting it to be (or not). Which seems to clash with the "get rid of all the crap that accumulated" part, so I don't understand.
Also, don't forget the comparator and latch (RS or monostable), otherwise it just oscillates forever. If you've already solved this problem, then you've probably done that, but just making sure...
Tim