Others have made some very good points, and 70 feet is not that far to cast in reality. The problem with 70 feet is effectively fishing with that much distance between you and the fly. Drag becomes a huge issue, and getting good hook sets as well.
From what I know about you Rod is you fish the Clinch primarily, and if you are looking a for a rod to handle "clinch distances" then I would look at a 9' 5wt. Z-Axis or One.
I fish a 9' 4 wt SP or Z-Axis on the Clinch every time I am out, and can cast as far as anyone on the river with it. However, that is just me, needless to say I might have a little different skill set then the majority of others on the river.
That is the reason I usually suggest and always suggest others stick with a 9' 5 wt, and it should do everything you need it to.
I would not look at the 9' + rods, when you add extra graphite they get clunky and heavy in the hand. I have never been a fan, and the longer rods are more useful for mending then they are distance casting IMO.