Jose,

I got mostly from winery websites (in most cases under Wines there are
links for individual bottlings, and most mention cepage or have links
to pdf tech sheets that do). I was quickly googling, and admit I didn't
neccesarily check for back vintages, so not neccessarily *exactly*
what's in my bottles. With that disclaimer, I just went and checked
most bottles I could easily reach, in most cases it's not mentioned on
the bottle (it is on the Barnett). While in cellar I also saw the
Franciscan Oakville and J. Phelps CS, neither mention other varietals
on the bottle but the Franciscan has Merlot and PV, and the Phelps
Merlot, PV, and CF. I also saw the BV Rutherford, which also has
(small) amounts of other grapes but doesn't mention on label.