There are a few posts and the end of this thread about adding a MiniFlex to a Taylor with the ES:
http://www.acousticguitarforum.com/f...d.php?t=274577
I am going to add one to my Taylor (514ce-n, nylon with the ES-N pickup) this week when my MiniFlex arrives. I ordered the Model 1 and I am going to add a second jack. Ken at MiniFlex confirmed that there is plenty of room for the second jack.
I did not investigate trying to wire a MiniFlex into the ES at all.
Hope that helps a bit.
Matt