Punbb is already the most flexible and easily customizable forum software. With the new styles 'per template' and hook/extension system tat will come in 1.3 it will literally leave the concurrence (if we can call it tat) miles away.
This, however does not mean, that it will ship bloated with a million features from which you would use like 3 or 4 of.
Important thing in punbb 1.3 will be: it will be possible to do pretty much everything you want in a proper why. By properly i mean, without touching the source code and in a way that your database also holds your mods.
AFAIK no other forum software does this.
Some very commonly requested features will be included in the core like: xmlfeeds, fancy url personalization, and some other stuff i don't know of.
Some quite popular requests, i hope, will be supported as official extensions.
Further customization can be achieved with other extensions.
I guess this answer to all you requests as punbb's flexibility will cover all that.
Ok, i ended up bragging about punbb as I always do.