I'm currently using Vaporheads for 100% VG. I too am allergic to PG, but I haven't had a problem with this. I do recommend you get your VG cut, the normal stuff is thick as honey. They'll dilute with distilled water but you'll still get the correct flavor and nic content. Pure VG seems to have it's drawbacks, like a complete lack of TH for me. I may try a small bottle of 80% VG to see if I react to it. Allergic reactions involving PG seem to have more to due with how pure the PG is; but proceed with caution, of course.
Good luck!