You'll ultimately have to do the inspections Mark suggests, but I continue to be hung up on the old adage:
Smoke on acceleration = rings
Smoke on engine braking = valve seals
I've been sitting here for two days trying to construct an argument to support that (mostly because I can't be sure I don't have it backwards and I'm trying to check myself). But I can't get a picture of the relative pressures in the crankcase, cylinder and head during all four strokes that helps me with the explanation.
Maybe someone else can help.
Anyway, you consistently report smoke on acceleration, throttle blipping, etc. Is there any smoke when you chop the throttle at speed? I realize you may need a buddy to check this. I don't want you riding while trying to look over your shoulder, or worse yet trying to see your cans in your mirrors!