If you wish to request a new feature, please add it to the bug tracker. If there is a feature listed here with an accompanying bug number, please add your vote of support so it may get done sooner. Or better yet, undertake it yourself. :)
If you really want a certain feature implemented, you may need to scratch our back a bit to bump it higher on the priority list..
These features currently exist only in the development tree. As they are backported, they will disappear from this list and appear on the Stable Changelog page, where they will accumulate until the next release. If there is something you wish to get backported sooner rather than later, leave comments in the appropriate bug ticket or on the mailing list.
A demo site running the latest -devel code can be found at http://po.shaftnet.org/po-devel-demo/. This is not considered stable enough for production, and as such may have unknown bugs and incomplete features. That said, the maintainer runs his personal site (http://www.shaftnet.org/po/) on the same code, so problems tend to get sorted out quickly.