Has an ectopic pregnancy's blastocyst ever been made to implant?
Not in an independently confirmed case.

A paper was once published claiming this was performed successfully:


Pearce JM, Manyonda IT, Chamberlain GV. Term delivery after intrauterine relocation of an ectopic pregancy. Br J Obs Gynaecol. 1994; 101:716–7.


This article and several others by the same author Malcolm Pearce were found to be fraudulent and were retracted:


Lock S. Lessons from the Pearce affair: handling scientific fraud. BMJ. 1995; 310(6994):1547-8.