I've talked to a few people around here that have come to the same conclusion. They also had the smoke at start up, and of course suspected their valve stem seals. Turned out after a couple new sets of seals it wasn't them at all. They all had one thing in common.... They all had broken in their motors on synthetic oil. And further.... they all had the same cure. Took the synth out, and went through their break in routine on dyno oil and cured their smoking issues. They were speculating of course but feel maybe the synth oil wasn't allowing proper ring seating.
I don't know, but one thing's for sure, they all cured their oil smoke issue.