You are right, 1075 is probably the most stable release for “cutting-edge” users, but we would appreciate testing of trunk during integration of BackPress.
We do intend to experiment with PingBacks and TrackBacks in topics via XML-RPC, and you could be right about spam, but we won’t know until we try. We will build out the spam tools provided by Akismet to try and meet the challenge of spam at the same time. There are also other ways in which we can utilise XML-RPC besides those two features which you may not have considered, we already have some cool ideas about user integration and content aggregation that should be driven by the needs of the hosted project. I hope you don’t leave us just for giving it a whirl
The “Press” names are mostly about branding and the they need not be taken literally. We can leverage a lot of good-will by associating with WordPress, and we intend to create better ways to integrate the two projects, regardless of where they are installed or hosted.