The problem with the grannie hubs is that as the holes are 110 pcd if you tried to drill them to 120 the new holes are right at the outer edge of the existing hub - ie hardly any metal between the hole and the outer edge of the hub

If you could find a jap 5 stud wheel they are something like 114pcd so the grannie hubs could possibly be adapted and still leave enough metal around the outer edge

BBS split rim Lms in jap fit could be a solution along with grannie hubs

remember though that you also have to find a suitable disc or resort to discs and bells - costs start rising then though and it starts to be uneconomical