Wouldn't it be simply epic if a Tformer had a sheet of paper as its alt mode, and folded itself origami style for its transformation?
I don't think a paper-doll transformer would be a good idea at all. It would be possibly the least effective transformer of all time. Now a roll of toilet paper transformer, functional!
i used to make paper transformers out of index cards at school when i was little, good way to not pay attention and have fun tf style.