A couple of options: MojoTone
has 5-hole, but they're out of stock at the moment.
Buy a 3-hole and drill between the holes
You could buy a jack plate and relocate the jack to the side of the bass, freeing up a hole.
You could buy the expensive MEC stacked single/dual-gang pot and combine the V/B to one stack.
You could go with the vol-vol setup and get a cheaper stacked pot for it.
The last option is to contact a metal fabrication place.