Lot of brands have the 80 wt thread now. A new manufacturing process allows it to be thin and strong.
I like the Masterpiece thread when it was 50/2. Now it's 50/3 to be stronger. I was given a set of Quilter's Select thread and it's really nice and it's 60 wt and 80 wt.
Watch the video here:
http://www.quiltersselect.com/