So, as previously indicated, let's add some wildcard support to the pg_hba.conf host name feature. After looking around a bit, two syntaxes appear to be on offer:
1. TCP Wrappers style, leading dot indicates suffix match. So .example.com matches anything.example.com. Not sure how useful that would be, but it could be implemented in about 3 lines of code.
2. Full regular expressions. I'd suggest the pg_ident.conf style, where a leading slash indicates a regex. An example could be /^dbserver\d\. With some code refactoring, this would also only take a few extra lines of code.