Can I generate a CSR file for mod_ssl on a different machine to the production box?

Solution 1:

SSL keys, CSRs, and certs aren't tied to a particular machine. You can generate the key and CSR anywhere you like, then copy it into place when your production machine is ready.

Solution 2:

You can generate the CSR on any machine you like, submit it and then re-use it.

Even the SSL certificates can be moved around from machine to machine.