[MOD EDIT: POST RETRIEVED FROM ARCHIVE]
Here is the most up-to-date version of my cabs. I also found out that the incorrect version number was in the filename string, not sure how that happened, but it did and I fixed it. I've also date stamped the filenames (yyyymmdd) so that people know which version is which. I don't know of any further updates that will need to be done, but these cabs will thread the MMS messages within the conversation in the WM Inbox. They will also allow you to set any of the notification options, whereas before, not everything could be changed. I sent myself a text message to start the conversation, then an MMS picture message. Screenshot to prove it too
If there are any further requests for things to be added, just provide the needed info (cab that does what you want or registry entries) and I can incorporate them as well. Testing of the USC and MetroPCS cabs to ensure they're working would be great as well. I'm also assuming the Sprint cab works since no one has said it doesn't, as someone before reported it as non-working, though I'm not sure why.
Click the picture for a larger shot