In the US, I only know of three: Shell Rotella T Synthetic (roughly 90% XHVI, 10% Group I), Shell Helix Ultra 5w40 (roughly 70% XHVI, 20% PAO, 10% Group V) and the various grades of domestic Castrol Syntec. Though according to the recently posted MSDS of Syntec, XHVI is only one base oil component and no percentages were given.
In Europe and other parts of the world, various grades of Shell's Helix oils contain XHVI.