EVO Pro by Brute Force is pretty powerful. Expensive but it works.

Another route to take is to come up with a good manual backlinking system that works and then putting together an outsourcing team to fulfill the system. Manual linking is normally the best way to go so by outsourcing you are doing the same thing as purchasing software (getting more done with less work) but taking advantage of the "human factor" that is valuable in the backlinking process.