It's an awfully far-fetched assumption to think that users wouldn't download apps outside of the app store if that were an option. People download windows/mac apps all the time.
I'm sure you can work around this somehow, but this isn't really the same as allowing unlimited and free distribution.
1) Share your unique device identifier with the developer.
2) The developer registers that device ID with Apple. Only 100 devices per developer may be registered in one year.
3) Apple signs a signing certificate which includes that device ID.
4) The developer signs the application binary with their private key and includes the Apple-signed certificate with the binary.
This is absolutely not useful for anything other than beta testing.
As to your other points, sign up for the Enterprise program.
http://manuals.info.apple.com/en_US/Enterprise_Deployment_Gu...
I can get out and push my car, but that doesn't make it a hybrid.
As to your other points, sign up for the Enterprise program.
The enterprise program does not allow for external distribution and is not useful (or even permitted) outside of large enterprise organizations.