One of my 7's has three Bartolini humbuckers, and they're all splittable. He has quite a few 7-string models, so you can choose one that sounds good when split. His pickups are shielded so well that even with the active boost, the noise was totally acceptable. Also, Bartolini would make you 7-string singles in a squared off bass housing, like a long thin 5 or 6-string bass chassis. They'd look different, but they'd sound right. If there's a way to use Bartolini that you're comfortable with, like 3 hums for example, I strongly recommend it. You will not be disappointed.