I finally have time to sit down and finish off the MSMQ transport provider using the WSE 2.0 release bits. There was yet another change between the intirm build I was using and the release bits that caused the transport provider to break. However, with a few minutes of tweaking this evening, I was able to get the transport to recompile and send/receive messages once again.
The last remaining piece is to make the channels endpoint aware so they send/receive on the proper channel given a specific EPR. Hopefully I can find the time this week to get that code in and then buff 'n polish.