I'd also recommended checking out Animal Plastics for racks. I have one from them and love it. I don't recall if they do locking ones, but as Nanci said, they will do custom requests. Perhaps locks are something they can do.
As for having BPs and corns share a rack... I've never had a BP and can't claim to know much about them. Hopefully someone else who is more familiar with their needs will chime in. That said, I know that corns and BPs are not native to the same continent, so I would be concerned about conflicting environmental needs (namely, heat). Like I said, I don't know all the details, but it's definitely something I'd do some research on before making a purchase!