I picked up some "Menthol Chill" from Vancity and found it to be a bit like huffing Vicks Vapo Rub. I also bought some 'Extreme Ice' from Rainbow Vapor which is good (and very 'fresh' with a small amount of peppermint flavor added) but not quite like halls. It's less 'medicinal' tasting than halls I would say.
Thinking about it I'll blend the two (roughly 50/50) and give you my take on that. ... Done. Give or take about 5% on the 50/50 blend it's got a small amount of a light tobacco like flavor that lingers on the tongue, decent throat hit and a bit of the 'Hallsy' mentholyptus flavor as well. This quick and dirty mix also has a nice little mouth tingle that lingers. This juice works out to roughly 21mg nic, 30pg/70vg mix. I can still taste a bit of residual peppermint as I just refilled with this mix without cleaning the tank or atomizer that I was vaping the 'Extreme Ice' with a bit of peppermint added but the tank was all but empty.
I may have to do this again as I quite like it. Thanks for getting the grey matter wondering.