There is some new information on Infogrames Unreal Tournament 2003 forum, letting us know that the upcoming bonuspack is delayed (thanks Blues). They also posted up info about what they done so far for the next patch. Here is a clip from the bonuspack posting:

A lot of unexpected issues have come up that have delayed the release of the bonus pack. We had to release patch 2186 before the bonuspack, because the bonuspack relies on some functionality added in 2186. Testing and releasing that patch took a little longer than expected. Then, we had to make a new version for Germany to satisfy the German requirements to avoid having the game "indexed". After that, we had to make another patch (2199) to address the server exploits that were published.