3 tier forum software

[^misantropia^]

The setup this software needs to be deployed on:

1. a small farm of front end servers
2. a (beefy) database server
3. an application server that sits between #1 and #2, only accessible from #1 through middleware / web services

Do any of you know of forum software that can cope with this scenario? Because I don't. Preferably PHP* but Perl or J2EE is acceptable too. ASP or ASP.NET: not really, unless no better alternative exists. But if need be, we'll make do with Mono or mod_asp. Money isn't an issue, building such a beast from the ground up is without doubt much more expensive**. Any help will be greatly appreciated.

* And preferably PHP4 on the front end, I kid you not, but the back end may use PHP5.
** You should see my hourly rate, it's enough to bankrupt small countries.

[creep]

i'm trying to think of a forum setup that ISN'T like that...

[prince1000]

http://punbb.org/
http://www.simplemachines.org/

[^misantropia^]

Thanks for the links, prince. But it appears I wasn't clear, so allow me to explain a little.

The front end can't directly communicate with the database* so all communication needs to go through the application server, using SOAP, XML-RPC or what-have-you.

Unfortunately, all the forum software I've found so far, talks directly to the database and in a way that isn't easily abstracted or wrapped (think code littered with SQL statements).

* security requirement, databases storing sensitive data may not be directly accessible by public machines