before making any suggestions, it would be good to see your current gearlist, that way we can see any weaknesses, and it will be easier to dial in your gear situation.
as far as pack recomondations, it really depends on your other gear choices, if your gearlist is under 10lbs, you will need a different pack than a 20 or 30lb load. it also depend on your resupply strategy, if you try a JMT thru-hike w/o resupply, you will have a heavier load to start out the hike, and will then need a heavier pack with better frame support.
last summer i did a 195 mile trek throught the sierras without a resupply, it was easier to plan, not having a ressuply, but i dont know if i would do it again, at the start of the hike i had almost 40lbs on my back, when my base weight was only 7.5lbs. it took my 9 days to finish the hike, i think if i had a couple ressuplys i could have done it quite a bit faster, and enjoyed the first few days more, because i wouldent have had the same weight in the begining.
I used a golite JAM, a ULA conduit is compareable to the JAM in size, and i assume performance. the JAM was excellent, and to this day remains my favorite backpack for almost all aplications.