Is there any way of doing an inverse telecine within Vegas? There are a couple IVTC property settings, but it's not clear how these are to be used.

Could this be scripted if support is not already there?

Lastly, to go back to a telcine format if the conversion does a repeat of the 5th frame, would a scripting approach be used to sort generating back a 3:2 variant?

Me thinks a plugin would be handy here.