Imagine a super mother plant with like 6 different strains grafted onto it, kinda like an apple tree with multiple grafts. That would be epic, especially if you flowered it out and they were all different color strains.i suppose you could veg out a rootstock plant and then graft several scions on to the rootstock plant while keeping a few leafy branches on the root stock plant to keep it alive.
it would be far quicker just to grow from seed and forgo the grafting. grafting is useful for slow growing plants like fruit trees, not rapidly growing plants like cannabis.