I did find some Black Currant wine base at homebrew supply but i'm not sure if that'd work.
Is there any particular reason for your concern with this? If it's the Vintner's Best version (or something similar), it's just listed as having some additional sugar and acid added to the juice concentrates. The SG listed is approximately 1.078. I don't see why it wouldn't work.
I haven't done it so I'm not sure what ratio would be best, but you could make a partial batch of mead and then add the wine base near the end of fermentation. For example if you're shooting for a 5 gallon batch, make a 4 gallon batch of mead as you normally would, and then add a gallon of the currant wine base (or more depending on what ratio you choose) once fermentation is a week or so in. Let it ferment out and see what you've got.