Your developers should not use @@servername to check things. They should be working cross database only, with 3 part, not 4 part, names.
I agree with Steve. I have a mirror that is setup with two different machines (each with a unique name, or course) and I have a DNS entire for a "virtual" server name that our application connections to. If we need to fail over we make a DNS change and they are now connected to the new principal. Why do your developers want to use 4-part naming?