The question somewhat doesn't make sense. A Bass VI is a type of baritone guitar, specifically one that has a 30" scale length. You can't just stretch any guitar to that scale length unless you swap out the neck. There are some baritones that are also a 30" scale length. Those could be described as being similar to a Bass VI. You wouldn't really "make a Bass VI" out of them. They're already a 30" baritone. And as far as converting a bass to have more strings, it's been done but it's a heck of a project.

If the true question is about tuning, then you can very likely get any baritone to be E1 to E2 with the right string gauge. For reference, a Bass VI is 30" scale length, tuned E1 to E2, and comes from the factory with .024-.084 strings. You can use an online string tension calculator to transpose that to whatever guitar you already have.