i take it this is possible since there are 3rd party vendors out there but how would one go about it? wouldn't you have to have some knowledge of the editing softwares internals, etc?
The SDK is a good start. You may also want to visit the DirectX plug-ins forum on this site. Finally look for "Wax" by DebugMode (www.debugmode.com) you can get a lot of additional transitions and effects for "free" (you may have to spend some time to get it to work right, and yet your mileage may vary on whether it finally works for you or not - I ran into crashes on exit with SVMS8 PE).