I discovered that VirtualBox does not allow the distribution of binaries. I should have suspected this, since there are no binaries in any Linux distribution, only on the official website.
The best we could get would be a build script, but, honestly, I've lost interest (although it's very worthwhile, since VirtualBox is clearly infinitely superior to qemu in terms of performance (Maybe I'm doing something wrong, because everywhere on the internet it says that qemu is faster because of KVM, although I can't see that at all.))