Two brands come to mind. Sugoi and Varivas. Varivas is fairly hard to find. It comes from Japan and has the least amount of memory I've seen in a flourocarbon line. The Sugoi is the way to go if you cant find the Varivas. The sugoi is just as abrasion resistant if not more then the P-line cxx. That stuff is almost indestructable. It is expensive, but if you know how to cast and not get too many backlashes, you can leave it on your reel for a long time. Just stretch it a little and your in buisness for like 6-10 months of fishing. It doesn't slip when you tie a regular knot either.

Good Luck
Cam