SCART is just a connector which includes various different signal types, including RGB, composite and so on... I'm vaguely aware of seeing the plans for that adaptor, and it is pretty simple, all you should have to do is separate out the signals and grounds to the BNC connectors or whatever are on your TV instead of the SCART plug. Electrically it should be exactly the same and so should work no problem.
As an aside, 23-pin D connectors are available if you have a good look around - I know I was able to get them in an electronics shop in Dublin the last time I needed them.
