I saw two votes that were contested. The first was when I was a teenager. The KH was being totally renovated, we had windows, and the vote was wether to get rid of the windows. It was pretty much split down the middle, the congregation was small, about 30-35 publishers. The vote was taken suddenly on a midweek meeting night, when some of the pro-window people were absent. We voted to get rid of the windows. I remember this was used as an example as to why you should never miss meetings, you might get screwed on a vote!
The other time was several years back when we voted on changing the meeting times. A few of the older elders wanted to move the midweek meeting up from 730 to 7pm. That went over like a lead balloon. We voted and it wasn't that close. Still it was a strange sight to not see a unanimous vote in a KH.