High Pressure, Low Rolling Resistance....Found Some!
 

Anyone ever look at Continental Vanco series tires? You can find them on TireRack.com. Some handle 70-psi, have low rolling resistance, and treadwear is outstanding. The Continental Vanco-8 and 4-Season look promising.

My stock size is 205/60R15, and I'm thinking about going 195/70R15. Should be ~4% larger circumference than stock plus much lower rolling resistance. Any thoughts?

LLR's are normally truck tires, they considerable reduce the vehicle's handling ability and must be driven very easily hence designed and made and used on trucks.

You HAVE to drive them super nice or they will NOT last!
It's like driving on eggs, you can make them last the lifetime of the vehicle but fail to drive them properly and you won't get 10,000 miles out of them. Yes, the rubber will wear out in no time if you don't.

Just look at the owner reviews, every single last automotive owner who put LLR's on their car failed to get over 20,000 miles out of them... Not saying it can't be done, the tires can easily do 100,000 - 200,000 and more, but unless you know how to drive them... And it's not an easy trick.

So at the very least a full size work pick up, it would help further if it was trailered and you have 4-5 years of driving like that behind you...

I suspect that the Bridgestone "Turanza T" tires I used a few times were pretty low in RR. They were very quiet and smooth.

They handled kinda bad at the car manufacturer's recommended pressure (IIRC, 30 or 35 psi), but much better at their maximum 44psi. At the lower pressure they lasted 80,000 miles and still had tread left when the sidewalls were too cracked. At 44psi a new set lasted at least 90,000 miles, I'm not exactly sure because by then I wasn't driving that car. At either pressure, I beat on them hard, so if you drive nice you could probably get 120,000 miles from them.

At the time they were sold with an unlimited mileage treadwear warranty that expired after 6 years. Now I think they sell them with 80,000 mile warranty.

From the tirerack.com reviews and other reviews, it seems the Vanco-8 can last a long long time with no special driving "mannerisms". The cost/benefit ratio seems pretty good.