great hand. i'd definitely like more of a read on the aggresor, but in the absence of that i probably have to call.
smells to me like the classic EP limp w/ AA, KK, QQ hoping to trap a late position raiser and everyone in between. he puts you on a jack that you're not going to lay down, and wants to protect against the flush and show how tricky he is limping with an overpair. 67s is the other strong possibility.
anyone you can reasonably describe as "tight" isn't holding J7 here, and i agree that 66 is pretty unlikely. i see this move time and time again with a flush draw, but i don't think that's where i'd put this guy. after you reraise, he's got to know that he probably needs to make his draw, so he takes a card off. the "auto call" leads me to believe that he's thinking that he's trapping you all along (ala: QQ / KK).
you're getting about 1.8:1 to call. if he's got two black queens, you're 70% to win, and you're even a slight favorite against 9

8

. hell, he could have something like 6

7

for bottom two. the only reasonable hand that you're a huge dog to is 77 (oh, and you're a HUGE dog).
if he's weak, your holding hasn't even crossed his mind, so bottom two or an overpair are automatic pushes for him.
speak - what hand did you put him on that made you have to think so hard?
gw-