I like the idea. Right now you either have to change the source code or use mod_security to achieve this, but I think the feature belongs to the server core.
But I think a new server directive is a better solution.
As Lars said (and I agree), it has nothing to do with security. Why do you provide such a "feature" then?
Because I believe that changing the signature prevents some automated tools from attacking the server.
I recently changed the signature of the Apache running on modsecurity.org (to pretend to be IIS5). As a result, I've started getting more IIS-related attacks than before. So, the signature does matter.
-- ModSecurity (http://www.modsecurity.org) [ Open source IDS for Web applications ]
