I believe verjus is the same thing as a common Persian cooking ingredient named "ab-gureh" a.k.a. sour grape juice. The descriptions match completely and according to some web sites they are one and the same. You can find sour grape juice at any Persian grocery store in Vancouver.
Sure do! EdibleBC on Granville Island stocks it; and I know this bc I work there and we just finished inventory for the year so there are DEF bottles on the shelf. Open 7 days a week 9am-7pm EXCEPT NY's Eve (closing @ 4pm) and Closed NYs Day.