$140,000 for a 2 acre sized liner, installed sounds pretty close. They also only last about 20 years on average for a good one. Bentonite, done right, will be pricey as well, but last for generations.
+1 on contacting Mike Otto...if nothing else, he may know some people to steer you toward from experience.
Rainman, they say that when you lose water during droughts, the bentonite layer, exposed to sun, will be dried and cracked and when it meets the water again, it will start leaking. I guess you are well-informed about this material. What do you think?
