Would it be useful to upload an enhancement I'd made to the Postfix/Dovecot/MySQL e-mail guide? I'd altered the virtual users table to allow for wildcard routing for mail servers handling multiple domains, eg. (all rules implicity limited to domains listed in the virtual domains table) (listed most-specific to least-specific, matching stops at the first rule matched so more-specific rules take precedence over less-specific ones):

• user X at domain xyzzy.com goes to local user A
• user X at any domain goes to local user B
• any user at domain xyzzy goes to local user C (domain catch-all rule)
• any user at any domain goes to local user D (global catch-all)

I use it in combination with local users rather than the virtual users/mailboxes described in the guide, but it should work the same for both.

I think you can just submit a pull request against Linode's GitHub repository. You'll probably need to make some sort of copyright/licensing arrangement. See their contributions page for more info.

I would say you can just fork it, but it's under a CC no-derivatives license. :(

I'd probably write a guide up myself, just the virtual users change is a small patch but the full thing's a bit bigger (backup mail server setup, PHP pages to make it easier to manage stuff, that sort of thing) and it'd go smoother that way. Plus I'd like to see if I can make both delivery and Dovecot try a system account first and then a virtual mailbox if there's no system account. I'm not sure it can be done, but it'd be nice. More things to do in my Copious Free Time. I swear, my to-do list is longer now than when I had managers overloading me.

Better documentation is always needed. If you don't have your own blog or something, you can always post to the tips and tricks forum. Afraid I can't help you with acquiring extra free time...