if it was me I'd go for the new valve body. if the rest of the transmission shifts fine then there's no point in throwing out a perfectly good set of gears and clutches. Not to mention that this could very well be the culprit (check valves blown out or something).
While your governor 'test' is not conclusive there's not a whole lot to go wrong there either and if it's engaged then not much more to be said..if it wasn't I reckon it would have been fried anyway.
haven't seen any
VB prices but heard in the region of $200-$300..and I know a tranny is going be around $1300 so the math seems pretty simple
.