If it comes to dragging them out would a Manitou telehandler do it I wonder?
If you want it out (with minimum disruption to surrounding area) then a cheap breaker is a good bet I think...assuming it was postcrete in the hole.
Its really good stuff - designed to do a job basically...saves a heap of time as it goes of very quick so you can stick posts in all day and not worry about props and bracing etc. I was speaking to a handyman once who was telling me his insane pricing for a fence...when we got down to why it was so expensive....well basically he was putting in 1 post a day!Postcrete, I've never used it.