IMO it would be impractical: the E on a 4-string bass is something like .100 or .105, but that's on a 34" scale. To achieve decent tension on a 24¾" scale, the string would need to be ludicrously heavy.
Then there's the practical question of whether the low B from a 5-string bass set would even fit through the tuner holes, along with the probability that it wouldn't intonate correctly if it did (the bridge on my Gothic V is already at the limit of its adjustment with the bottom string tuned to Bb)
I use D'Addario 13-62 baritone strings on my Gothic V tuned to Bb - even with such a heavy gauge string it flaps around a bit.
Yes, it's tempting with the Warpig to take everything to the extreme :twisted: but you can have too much of a good thing... ;)